Browse
  • PartIIIBuilding Planning and Construction

    CHAPTER3
    BUILDING PLANNING  

    SECTIONR301
    DESIGN CRITERIA  

    R301.1 Application.

    Buildings and structures, and parts thereof, shall be constructed to safely support all loads, including dead loads, live loads, roof loads, flood loads, snow loads, wind loads and seismic loads as prescribed by this code. The construction of buildings and structures in accordance with the provisions of this code shall result in a system that provides a complete load path that meets the requirements for the transfer of loads from their point of origin through the load-resisting elements to the foundation. Buildings and structures constructed as prescribed by this code are deemed to comply with the requirements of this section.

    R301.1.1 Alternative provisions.

    As an alternative to the requirements in Section R301.1, the following standards are permitted subject to the limitations of this code and the limitations therein. Where engineered design is used in conjunction with these standards, the design shall comply with the International Building Code.

    R301.1.2 Construction systems.

    The requirements of this code are based on platform and balloon-frame construction for light-frame buildings. The requirements for concrete and masonry buildings are based on a balloon framing system. Other framing systems must have equivalent detailing to ensure force transfer, continuity and compatible deformations.

    R301.1.3 Engineered design.

    Where a building of otherwise conventional construction contains structural elements exceeding the limits of Section R301 or otherwise not conforming to this code, these elements shall be designed in accordance with accepted engineering practice. The extent of such design need only demonstrate compliance of nonconventional elements with other applicable provisions and shall be compatible with the performance of the conventional framed system. Engineered design in accordance with the International Building Code is permitted for buildings and structures, and parts thereof, included in the scope of this code.

    R301.2 Climatic and geographic design criteria.

    Buildings shall be constructed in accordance with the provisions of this code as limited by the provisions of this section. Additional criteria shall be established by the local jurisdiction and set forth in Table R301.2(1).

    TABLE R301.2(1)

    CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA

    GROUNDSNOWLOADWIND DESIGNSEISMICDESIGNCATEGORYfSUBJECT TO DAMAGE FROMWINTERDESIGNTEMPeICE BARRIERUNDERLAYMENTREQUIREDhFLOODHAZARDSgAIRFREEZINGINDEXiMEANANNUALTEMPj
    Speedd(mph)TopographiceffectskSpecial windregionlWind-bornedebris zonemWeatheringaFrost linedepthbTermitec

    For SI: 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.

    1. a.Weathering may require a higher strength concrete or grade of masonry than necessary to satisfy the structural requirements of this code. The weathering column shall be filled in with the weathering index, “negligible,” “moderate” or “severe” for concrete as determined from Figure R301.2(3). The grade of masonry units shall be determined from ASTM C 34, C 55, C 62, C 73, C 90, C 129, C 145, C 216 or C 652.

    2. b.The frost line depth may require deeper footings than indicated in Figure R403.1(1). The jurisdiction shall fill in the frost line depth column with the minimum depth of footing below finish grade.

    3. c.The jurisdiction shall fill in this part of the table to indicate the need for protection depending on whether there has been a history of local subterranean termite damage.

    4. d.The jurisdiction shall fill in this part of the table with the wind speed from the basic wind speed map [Figure R301.2(4)A]. Wind exposure category shall be determined on a site-specific basis in accordance with Section R301.2.1.4.

    5. e.The outdoor design dry-bulb temperature shall be selected from the columns of 971/2-percent values for winter from Appendix D of the International Plumbing Code. Deviations from the Appendix D temperatures shall be permitted to reflect local climates or local weather experience as determined by the building official.

    6. f.The jurisdiction shall fill in this part of the table with the seismic design category determined from Section R301.2.2.1.

    7. g.The jurisdiction shall fill in this part of the table with (a) the date of the jurisdiction’s entry into the National Flood Insurance Program (date of adoption of the first code or ordinance for management of flood hazard areas), (b) the date(s) of the Flood Insurance Study and (c) the panel numbers and dates of the currently effective FIRMs and FBFMs or other flood hazard map adopted by the authority having jurisdiction, as amended.

    8. h.In accordance with Sections R905.1.2, R905.4.3.1, R905.5.3.1, R905.6.3.1, R905.7.3.1 and R905.8.3.1, where there has been a history of local damage from the effects of ice damming, the jurisdiction shall fill in this part of the table with “YES.” Otherwise, the jurisdiction shall fill in this part of the table with “NO.”

    9. i.The jurisdiction shall fill in this part of the table with the 100-year return period air freezing index (BF-days) from Figure R403.3(2) or from the 100-year (99 percent) value on the National Climatic Data Center data table “Air Freezing Index-USA Method (Base 32°F).”

    10. j.The jurisdiction shall fill in this part of the table with the mean annual temperature from the National Climatic Data Center data table “Air Freezing Index-USA Method (Base 32°F).”

    11. k.In accordance with Section R301.2.1.5, where there is local historical data documenting structural damage to buildings due to topographic wind speed-up effects, the jurisdiction shall fill in this part of the table with “YES.” Otherwise, the jurisdiction shall indicate “NO” in this part of the table.

    12. l.In accordance with Figure R301.2(4)A, where there is local historical data documenting unusual wind conditions, the jurisdiction shall fill in this part of the table with “YES” and identify any specific requirements. Otherwise, the jurisdiction shall indicate “NO” in this part of the table.

    13. m.In accordance with Section R301.2.1.2.1, the jurisdiction shall indicate the wind-borne debris wind zone(s). Otherwise, the jurisdiction shall indicate “NO” in this part of the table.

    TABLE R301.2(2)

    COMPONENT AND CLADDING LOADS FOR A BUILDING WITH A MEAN ROOF HEIGHT OF 30 FEET LOCATED IN EXPOSURE B (ASD) (psf)a, b, c, d, e

    ZONEEFFECTIVEWIND AREA(feet2)ULTIMATE DESIGN WIND SPEED, VULT (mph)
    110115120130140150160170180
    Roof 0 to 7 degrees11010.0-13.010.0-14.010.0-15.010.0-18.010.0-21.09.9-24.011.2-27.012.6-31.014.2-35.0
    12010.0-12.010.0-13.010.0-15.010.0-17.010.0-20.09.2-23.010.6-26.011.9-30.013.3-34.1
    15010.0-12.010.0-13.010.0-14.010.0-17.010.0-19.08.5-22.010.0-26.010.8-29.012.2-32.9
    110010.0-11.010.0-13.010.0-14.010.0-16.010.0-19.07.8-22.010.0-25.010.0-28.011.3-32.0
    21010.0-21.010.0-23.010.0-26.010.0-30.010.0-35.09.9-40.011.2-46.012.6-52.014.2-58.7
    22010.0-19.010.0-21.010.0-23.010.0-27.010.0-31.09.2-36.010.6-41.011.9-46.013.3-52.4
    25010.0-16.010.0-18.010.0-19.010.0-23.010.0-26.08.5-30.010.0-34.010.8-39.012.2-44.1
    210010.0-14.010.0-15.010.0-16.010.0-19.010.0-22.07.8-26.010.0-30.010.0-33.011.3-37.9
    31010.0-33.010.0-36.010.0-39.010.0-46.010.0-53.09.9-61.011.2-69.012.6-78.014.2-88.3
    32010.0-27.010.0-29.010.0-32.010.0-38.010.0-44.09.2-50.010.6-57.011.9-65.013.3-73.1
    35010.0-19.010.0-21.010.0-23.010.0-27.010.0-32.08.5-36.010.0-41.010.8-47.012.2-53.1
    310010.0-14.010.0-15.010.0-16.010.0-19.010.0-22.07.8-26.010.0-30.010.0-33.011.3-37.9
    Roof > 7 to 27 degrees11010.0-11.010.0-13.010.0-14.010.5-16.012.2-19.014.0-22.015.9-25.017.9-28.020.2-32.0
    12010.0-11.010.0-12.010.0-13.010.0-16.011.1-18.012.8-21.014.5-24.016.4-27.018.4-31.1
    15010.0-11.010.0-12.010.0-13.010.0-15.010.0-18.011.1-20.012.7-23.014.3-26.016.0-29.9
    110010.0-10.010.0-11.010.0-12.010.0-15.010.0-17.09.9-20.011.2-22.012.6-25.014.2-29.0
    21010.0-20.010.0-22.010.0-24.010.5-29.012.2-33.014.0-38.015.9-44.017.9-49.020.2-55.8
    22010.0-19.010.0-20.010.0-22.010.0-26.011.1-31.012.8-35.014.5-40.016.4-45.018.4-51.2
    25010.0-16.010.0-18.010.0-20.010.0-23.010.0-27.011.1-31.012.7-35.014.3-40.016.0-45.4
    210010.0-15.010.0-16.010.0-18.010.0-21.010.0-24.09.9-28.011.2-32.012.6-36.014.2-40.9
    31010.0-30.010.0-33.010.0-36.010.5-43.012.2-49.014.0-57.015.9-65.017.9-73.020.2-82.4
    32010.0-28.010.0-31.010.0-34.010.0-40.011.1-46.012.8-53.014.5-60.016.4-68.018.4-77.0
    35010.0-26.010.0-28.010.0-31.010.0-36.010.0-42.011.1-48.012.7-55.014.3-62.016.0-69.9
    310010.0-24.010.0-26.010.0-28.010.0-33.010.0-39.09.9-44.011.2-51.012.6-57.014.2-64.6
    Roof > 27 to 45 degrees11011.9-13.013.1-14.014.2-15.016.7-18.019.4-21.022.2-24.025.3-27.028.5-31.032.0-35.0
    12011.6-12.012.7-13.013.8-14.016.2-17.018.8-20.021.6-23.024.6-26.027.7-29.031.1-33.2
    15011.2-11.012.2-12.013.3-13.015.6-16.018.1-18.020.8-21.023.6-24.026.7-27.029.9-30.8
    110010.9-10.011.9-11.012.9-12.015.1-15.017.6-17.020.2-20.022.9-22.025.9-25.029.0-29.0
    21011.9-15.013.1-16.014.2-18.016.7-21.019.4-24.022.2-28.025.3-32.028.5-36.032.0-40.9
    22011.6-14.012.7-16.013.8-17.016.2-20.018.8-23.021.6-27.024.6-30.027.7-34.031.1-39.1
    25011.2-13.012.2-15.013.3-16.015.6-19.018.1-22.020.8-25.023.6-29.026.7-32.029.9-36.8
    210010.9-13.011.9-14.012.9-15.015.1-18.017.6-21.020.2-24.022.9-27.025.9-31.029.0-35.0
    31011.9-15.013.1-16.014.2-18.016.7-21.019.4-24.022.2-28.025.3-32.028.5-36.032.0-40.9
    32011.6-14.012.7-16.013.8-17.016.2-20.018.8-23.021.6-27.024.6-30.027.7-34.031.1-39.1
    35011.2-13.012.2-15.013.3-16.015.6-19.018.1-22.020.8-25.023.6-29.026.7-32.029.9-36.8
    310010.9-13.011.9-14.012.9-15.015.1-18.017.6-21.020.2-24.022.9-27.025.9-31.029.0-35.0
    Wall41013.1-14.014.3-15.015.5-16.018.2-19.021.2-22.024.3-26.027.7-30.031.2-33.035.0-37.9
    42012.5-13.013.6-14.014.8-16.017.4-19.020.2-22.023.2-25.026.4-28.029.7-32.033.4-36.4
    45011.7-12.012.8-14.013.9-15.016.3-17.019.0-20.021.7-23.024.7-27.027.9-30.031.3-34.3
    410011.1-12.012.1-13.013.2-14.015.5-17.018.0-19.020.6-22.023.5-25.026.5-29.029.832.7
    450010.0-10.010.6-11.011.6-12.013.6-15.015.8-17.018.1-20.020.6-22.023.2-25.026.1-29.0
    51013.1-17.014.3-19.015.5-20.018.2-24.021.2-28.024.3-32.027.7-37.031.2-41.035.0-46.8
    52012.5-16.013.6-17.014.8-19.017.4-22.020.2-26.023.2-30.026.4-34.029.7-39.033.4-43.7
    55011.7-14.012.8-16.013.9-17.016.3-20.019.0-23.021.7-27.024.7-31.027.9-35.031.3-39.5
    510011.1-13.012.1-14.013.2-16.015.5-19.018.0-22.020.6-25.023.5-28.026.5-32.029.8-36.4
    550010.0-10.010.6-11.011.6-12.013.6-15.015.8-17.018.1-20.020.6-22.023.2-25.026.1-29.0

    For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 0.0479 kPa.

    1. a.The effective wind area shall be equal to the span length multiplied by an effective width. This width shall be permitted to be not less than one-third the span length. For cladding fasteners, the effective wind area shall not be greater than the area that is tributary to an individual fastener.

    2. b.For effective areas between those given, the load shall be interpolated or the load associated with the lower effective area shall be used.

    3. c.Table values shall be adjusted for height and exposure by multiplying by the adjustment coefficient in Table R301.2(3).

    4. d.See Figure R301.2(7) for location of zones.

    5. e.Plus and minus signs signify pressures acting toward and away from the building surfaces.

    TABLE R301.2(3)

    HEIGHT AND EXPOSURE ADJUSTMENT COEFFICIENTS FOR TABLE R301.2(2)

    MEAN ROOF HEIGHTEXPOSURE
    BCD
    151.001.211.47
    201.001.291.55
    251.001.351.61
    301.001.401.66
    351.051.451.70
    401.091.491.74
    451.121.531.78
    501.161.561.81
    551.191.591.84
    601.221.621.87

    For SI: °C = [(°F)-32]/1.8.

    FIGURE R301.2(1)

    ISOLINES OF THE 971/2-PERCENT WINTER (DECEMBER, JANUARY AND FEBRUARY) DESIGN TEMPERATURES (°F)

    FIGURE R301.2(2)

    SEISMIC DESIGN CATEGORIES—SITE CLASS D

    1. a.Alaska and Hawaii are classified as severe and negligible, respectively.

    2. b.Lines defining areas are approximate only. Local conditions may be more or less severe than indicated by region classification. A severe classification is where weather conditions result in significant snowfall combined with extended periods during which there is little or no natural thawing causing deicing salts to be used extensively.

    FIGURE R301.2(3)

    WEATHERING PROBABILITY MAP FOR CONCRETEa, b

    Notes:

    1. 1.Values are nominal design 3-second gust wind speeds in miles per hour (m/s) at 33 ft (10m) above ground for Exposure C category.

    2. 2.Linear interpolation between contours is permitted.

    3. 3.Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area.

    4. 4.Mountainous terrain, gorges, ocean promontories, and special wind region shall be exmined for unusual wind conditions.

    5. 5.Wind speeds correspond to approximately a 7% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00143, MRI = 700 Years).

    FIGURE R301.2(4)A

    ULTIMATE DESIGN WIND SPEEDS

    Notes:

    1. 1.Values are nominal design 3-second gust wind speeds in miles per hour (m/s) at 33 ft (10m) above ground for Exposure C category.

    2. 2.Linear interpolation between contours is permitted.

    3. 3.Islands and coastal areas outside the last contour shall use the last wind speed contour of the coastal area.

    4. 4.Mountainous terrain, gorges, ocean promontories, and special wind region shall be exmined for unusual wind conditions.

    5. 5.Wind speeds correspond to approximately a 7% probability of exceedance in 50 years (Annual Exceedance Probability = 0.00143, MRI = 700 Years).

    FIGURE R301.2(4)B

    REGIONS WHERE WIND DESIGN IS REQUIRED

    For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile = 1.61 km.

    1. a.In CS areas, site-specific Case Studies are required to establish ground snow loads. Extreme local variations in ground snow loads in these areas preclude mapping at this scale.

    2. b.Numbers in parentheses represent the upper elevation limits in feet for the ground snow load values presented below. Site-specific case studies are required to establish ground snow loads at elevations not covered.

    For SI: 1 foot = 304.8 mm, 1 pound per square foot = 0.0479 kPa, 1 mile = 1.61 km.

    1. a.In CS areas, site-specific Case Studies are required to establish ground snow loads. Extreme local variations in ground snow loads in theses areas preclude mapping at this scale.

    2. b.Numbers in parentheses represent the upper elevation limits in feet for the ground snow load values presented below. Site-specific case studies are required to establish ground snow loads at elevations not covered.

    FIGURE R301.2(5)

    GROUND SNOW LOADS, Pg, FOR THE UNITED STATES (lb/ft2)

    Note: Lines defining areas are approximate only. Local conditions may be more or less severe than indicated by the region classification.

    FIGURE R301.2(6)

    TERMITE INFESTATION PROBABILITY MAP

    For SI: 1 foot = 304.8 mm, 1 degree = 0.0175 rad.

    Note: a = 4 feet in all cases.

    FIGURE R301.2(7)

    COMPONENT AND CLADDING PRESSURE ZONES

    R301.2.1 Wind design criteria.

    Buildings and portions thereof shall be constructed in accordance with the wind provisions of this code using the ultimate design wind speed in Table R301.2(1) as determined from Figure R301.2(4)A. The structural provisions of this code for wind loads are not permitted where wind design is required as specified in Section R301.2.1.1. Where different construction methods and structural materials are used for various portions of a building, the applicable requirements of this section for each portion shall apply. Where not otherwise specified, the wind loads listed in Table R301.2(2) adjusted for height and exposure using Table R301.2(3) shall be used to determine design load performance requirements for wall coverings, curtain walls, roof coverings, exterior windows, skylights, garage doors and exterior doors. Asphalt shingles shall be designed for wind speeds in accordance with Section R905.2.4. A continuous load path shall be provided to transmit the applicable uplift forces in Section R802.11.1 from the roof assembly to the foundation.

    R301.2.1.1 Wind limitations and wind design required.

    The wind provisions of this code shall not apply to the design of buildings where wind design is required in accordance with Figure R301.2(4)B.

    Exceptions:

    1. 1.For concrete construction, the wind provisions of this code shall apply in accordance with the limitations of Sections R404 and R608.

    2. 2.For structural insulated panels, the wind provisions of this code shall apply in accordance with the limitations of Section R610.

    3. 3.For cold-formed steel light-frame construction, the wind provisions of this code shall apply in accordance with the limitations of Sections R505, R603 and R804.

    In regions where wind design is required in accordance with Figure R301.2(4)B, the design of buildings for wind loads shall be in accordance with one or more of the following methods:

    The elements of design not addressed by the methods in Items 1 through 5 shall be in accordance with the provisions of this code.

    Where ASCE 7 or the International Building Code is used for the design of the building, the wind speed map and exposure category requirements as specified in ASCE 7 and the International Building Code shall be used.

    R301.2.1.1.1 Sunrooms.

    Sunrooms shall comply with AAMA/NPEA/NSA 2100. For the purpose of applying the criteria of AAMA/NPEA/NSA 2100 based on the intended use, sunrooms shall be identified as one of the following categories by the permit applicant, design professional or the property owner or owner’s agent in the construction documents. Component and cladding pressures shall be used for the design of elements that do not qualify as main windforce-resisting systems. Main windforce-resisting system pressures shall be used for the design of elements assigned to provide support and stability for the overall sunroom.

    • Category I: A thermally isolated sunroom with walls that are open or enclosed with insect screening or 0.5 mm (20 mil) maximum thickness plastic film. The space is nonhabitable and unconditioned.

    • Category II: A thermally isolated sunroom with enclosed walls. The openings are enclosed with translucent or transparent plastic or glass. The space is nonhabitable and unconditioned.

    • Category III: A thermally isolated sunroom with enclosed walls. The openings are enclosed with translucent or transparent plastic or glass. The sunroom fenestration complies with additional requirements for air infiltration resistance and water penetration resistance. The space is nonhabitable and unconditioned.

    • Category IV: A thermally isolated sunroom with enclosed walls. The sunroom is designed to be heated or cooled by a separate temperature control or system and is thermally isolated from the primary structure. The sunroom fenestration complies with additional requirements for water penetration resistance, air infiltration resistance and thermal performance. The space is nonhabitable and conditioned.

    • Category V: A sunroom with enclosed walls. The sunroom is designed to be heated or cooled and is open to the main structure. The sunroom fenestration complies with additional requirements for water penetration resistance, air infiltration resistance and thermal performance. The space is habitable and conditioned.

    R301.2.1.2 Protection of openings.

    Exterior glazing in buildings located in windborne debris regions shall be protected from windborne debris. Glazed opening protection for windborne debris shall meet the requirements of the Large Missile Test of ASTM E 1996 and ASTM E 1886 as modified in Section 301.2.1.2.1. Garage door glazed opening protection for windborne debris shall meet the requirements of an approved impact-resisting standard or ANSI/DASMA 115.

    Exception: Wood structural panels with a thickness of not less than 7/16 inch (11 mm) and a span of not more than 8 feet (2438 mm) shall be permitted for opening protection. Panels shall be precut and attached to the framing surrounding the opening containing the product with the glazed opening. Panels shall be predrilled as required for the anchorage method and shall be secured with the attachment hardware provided. Attachments shall be designed to resist the component and cladding loads determined in accordance with either Table R301.2(2) or ASCE 7, with the permanent corrosion-resistant attachment hardware provided and anchors permanently installed on the building. Attachment in accordance with Table R301.2.1.2 is permitted for buildings with a mean roof height of 45 feet (13, 728 mm) or less where the ultimate design wind speed, Vult, is 180 mph (290 kph) or less.

    TABLE R301.2.1.2

    WINDBORNE DEBRIS PROTECTION FASTENING SCHEDULE FOR WOOD STRUCTURAL PANELSa, b, c, d

    FASTENER TYPEFASTENER SPACING (inches)a, b
    Panelspan ≤4 feet4 feet <panel span ≤ 6 feet6 feet <panel span ≤ 8 feet
    No. 8 wood screw basedanchor with 2-inch embedmentlength16108
    No. 10 wood screw basedanchor with 2-inch embedmentlength16129
    1/4-inch lag screw based anchorwith 2-inch embedment length161616

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound = 4.448 N, 1 mile per hour = 0.447 m/s.

    1. a.This table is based on 180 mph ultimate design wind speeds, Vult, and a 33-foot mean roof height.

    2. b.Fasteners shall be installed at opposing ends of the wood structural panel. Fasteners shall be located not less than 1 inch from the edge of the panel.

    3. c.Anchors shall penetrate through the exterior wall covering with an embedment length of not less than 2 inches into the building frame. Fasteners shall be located not less than 21/2 inches from the edge of concrete block or concrete.

    4. d.Panels attached to masonry or masonry/stucco shall be attached using vibration-resistant anchors having an ultimate withdrawal capacity of not less than 1,500 pounds.

    R301.2.1.2.1 Application of ASTM E 1996.

    The text of Section 2.2 of ASTM E 1996 shall be substituted as follows:

    • 2.2 ASCE Standard:

      ASCE 7-10 American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures

      The text of Section 6.2.2 of ASTM E 1996 shall be substituted as follows:

    • 6.2.2 Unless otherwise specified, select the wind zone based on the ultimate design wind speed, Vult, as follows:

    • 6.2.2.1 Wind Zone 1–130 mph ≤ ultimate design wind speed, Vult < 140 mph.

    • 6.2.2.2 Wind Zone 2–140 mph ≤ ultimate design wind speed, Vult < 150 mph at greater than 1 mile (1.6 km) from the coastline. The coastline shall be measured from the mean high water mark.

    • 6.2.2.3 Wind Zone 3–150 mph (58 m/s) ≤ ultimate design wind speed, Vult ≤ 170 mph (76 m/s), or 140 mph (54 m/s) ≤ ultimate design wind speed, Vult ≤ 170 mph (76 m/s) and within 1 mile (1.6 km) of the coastline. The coastline shall be measured from the mean high water mark.

    • 6.2.2.4 Wind Zone 4–ultimate design wind speed, Vult > 170 mph (76 m/s).

    R301.2.1.3 Wind speed conversion.

    Where referenced documents are based on nominal design wind speeds and do not provide the means for conversion between ultimate design wind speeds and nominal design wind speeds, the ultimate design wind speeds, Vult, of Figure R301.2(4)A shall be converted to nominal design wind speeds, Vasd, using Table R301.2.1.3.

    TABLE R301.2.1.3

    WIND SPEED CONVERSIONSa

    Vult110115120130140150160170180190200
    Vasd858993101108116124132139147155

    For SI: 1 mile per hour = 0.447 m/s.

    1. a.Linear interpolation is permitted.

    R301.2.1.4 Exposure category.

    For each wind direction considered, an exposure category that adequately reflects the characteristics of ground surface irregularities shall be determined for the site at which the building or structure is to be constructed. For a site located in the transition zone between categories, the category resulting in the largest wind forces shall apply. Account shall be taken of variations in ground surface roughness that arise from natural topography and vegetation as well as from constructed features. For a site where multiple detached one- and two-family dwellings, townhouses or other structures are to be constructed as part of a subdivision or master-planned community, or are otherwise designated as a developed area by the authority having jurisdiction, the exposure category for an individual structure shall be based upon the site conditions that will exist at the time when all adjacent structures on the site have been constructed, provided that their construction is expected to begin within one year of the start of construction for the structure for which the exposure category is determined. For any given wind direction, the exposure in which a specific building or other structure is sited shall be assessed as being one of the following categories:

    1. 1.Exposure B. Urban and suburban areas, wooded areas or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger. Exposure B shall be assumed unless the site meets the definition of another type exposure.

    2. 2.Exposure C. Open terrain with scattered obstructions, including surface undulations or other irregularities, having heights generally less than 30 feet (9144 mm) extending more than 1,500 feet (457 m) from the building site in any quadrant. This exposure shall also apply to any building located within Exposure B type terrain where the building is directly adjacent to open areas of Exposure C type terrain in any quadrant for a distance of more than 600 feet (183 m). This category includes flat, open country and grasslands.

    3. 3.Exposure D. Flat, unobstructed areas exposed to wind flowing over open water, smooth mud flats, salt flats and unbroken ice for a distance of not less than 5,000 feet (1524 m). This exposure shall apply only to those buildings and other structures exposed to the wind coming from over the unob structed area. Exposure D extends downwind from the edge of the unobstructed area a distance of 600 feet (183 m) or 20 times the height of the building or structure, whichever is greater.

    R301.2.1.5 Topographic wind effects.

    In areas designated in Table R301.2(1) as having local historical data documenting structural damage to buildings caused by wind speed-up at isolated hills, ridges and escarpments that are abrupt changes from the general topography of the area, topographic wind effects shall be considered in the design of the building in accordance with Section R301.2.1.5.1 or in accordance with the provisions of ASCE 7. See Figure R301.2.1.5.1(1) for topographic features for wind speed-up effect.

    In these designated areas, topographic wind effects shall apply only to buildings sited on the top half of an isolated hill, ridge or escarpment where all of the following conditions exist:

    1. 1.The average slope of the top half of the hill, ridge or escarpment is 10 percent or greater.

    2. 2.The hill, ridge or escarpment is 60 feet (18 288 mm) or greater in height for Exposure B, 30 feet (9144 mm) or greater in height for Exposure C, and 15 feet (4572 mm) or greater in height for Exposure D.

    3. 3.The hill, ridge or escarpment is isolated or unobstructed by other topographic features of similar height in the upwind direction for a distance measured from its high point of 100 times its height or 2 miles (3.2 km), whichever is less. See Figure R301.2.1.5.1(3) for upwind obstruction.

    4. 4.The hill, ridge or escarpment protrudes by a factor of two or more above the height of other upwind topographic features located in any quadrant within a radius of 2 miles (3.2 km) measured from its high point.

    R301.2.1.5.1 Simplified topographic wind speedup method.

    As an alternative to the ASCE 7 topographic wind provisions, the provisions of Section R301.2.1.5.1 shall be permitted to be used to design for wind speed-up effects, where required by Section R301.2.1.5.

    Structures located on the top half of isolated hills, ridges or escarpments meeting the conditions of Section R301.2.1.5 shall be designed for an increased basic wind speed as determined by Table R301.2.1.5.1. On the high side of an escarpment, the increased basic wind speed shall extend horizontally downwind from the edge of the escarpment 1.5 times the horizontal length of the upwind slope (1.5L) or 6 times the height of the escarpment (6H), whichever is greater. See Figure R301.2.1.5.1(2) for where wind speed increase is applied.

    TABLE R301.2.1.5.1

    ULTIMATE DESIGN WIND SPEED MODIFICATION FOR TOPOGRAPHIC WIND EFFECTa, b

    ULTIMATE DESIGNWIND SPEED FROMFIGURE R301.2(4)A(mph)AVERAGE SLOPE OF THE TOP HALF OF HILL, RIDGE OR ESCARPMENT (percent)
    0.100.1250.150.1750.200.230.25
    Required ultimate design wind speed-up, modified for topographic wind speed-up (mph)
    110132137142147152158162
    115138143148154159165169
    120144149155160166172176
    130156162168174179N/AN/A
    140168174181N/AN/AN/AN/A
    150180N/AN/AN/AN/AN/AN/A

    For SI: 1 mile per hour = 0.447 m/s, 1 foot = 304.8 mm.

    1. a.Table applies to a feature height of 500 feet or less and dwellings sited a distance equal or greater than half the feature height.

    2. b.Where the ultimate design wind speed as modified by Table R301.2.1.5.1 equals or exceeds 140 miles per hour, the building shall be considered as “wind design required” in accordance with Section R301.2.1.1.

    Note: H/2 determines the measurement point for Lh. L is twice Lh.

    FIGURE R301.2.1.5.1(1)

    TOPOGRAPHIC FEATURES FOR WIND SPEED-UP EFFECT

    FIGURE R301.2.1.5.1(2)

    ILLUSTRATION OF WHERE ON A TOPOGRAPHIC FEATURE, WIND SPEED INCREASE IS APPLIED

    FIGURE R301.2.1.5.1(3)

    UPWIND OBSTRUCTION

    R301.2.2 Seismic provisions.

    The seismic provisions of this code shall apply as follows:

    1. 1.Townhouses in Seismic Design Categories C, D0, D1 and D2.

    2. 2.Detached one- and two-family dwellings in Seismic Design Categories, D0, D1 and D2.

    R301.2.2.1 Determination of seismic design category.

    Buildings shall be assigned a seismic design category in accordance with Figure R301.2(2).

    R301.2.2.1.1 Alternate determination of seismic design category.

    The seismic design categories and corresponding short-period design spectral response accelerations, SDS shown in Figure R301.2(2) are based on soil Site Class D, as defined in Section 1613.3.2 of the International Building Code. If soil conditions are other than Site Class D, the short-period design spectral response accelerations, SDS, for a site can be determined in accordance with Section 1613.3 of the International Building Code. The value of SDS determined in accordance with Section 1613.3 of the International Building Code is permitted to be used to set the seismic design category in accordance with Table R301.2.2.1.1, and to interpolate between values in Tables R602.10.3(3), R603.9.2(1) and other seismic design requirements of this code.

    TABLE R301.2.2.1.1

    SEISMIC DESIGN CATEGORY DETERMINATION

    CALCULATED SDSSEISMIC DESIGN CATEGORY
    SDS ≤ 0.17gA
    0.17g < SDS ≤ 0.33gB
    0.33g < SDS ≤ 0.50gC
    0.50g < SDS ≤ 0.67gD0
    0.67g < SDS ≤ 0.83gD1
    0.83g < SDS < 1.25gD2
    1.25g < SDSE

    R301.2.2.1.2 Alternative determination of Seismic Design Category E.

    Buildings located in Seismic Design Category E in accordance with Figure R301.2(2) are permitted to be reclassified as being in Seismic Design Category D2 provided that one of the following is done:

    1. 1.A more detailed evaluation of the seismic design category is made in accordance with the provisions and maps of the International Building Code. Buildings located in Seismic Design Category E in accordance with Table R301.2.2.1.1, but located in Seismic Design Category D in accordance with the International Building Code, shall be permitted to be designed using the Seismic Design Category D2 requirements of this code.

    2. 2.Buildings located in Seismic Design Category E that conform to the following additional restrictions are permitted to be constructed in accordance with the provisions for Seismic Design Category D2 of this code:

      1. 2.1.All exterior shear wall lines or braced wall panels are in one plane vertically from the foundation to the uppermost story.

      2. 2.2.Floors shall not cantilever past the exterior walls.

      3. 2.3.The building is within the requirements of Section R301.2.2.2.5 for being considered as regular.

    R301.2.2.2 Seismic Design Category C.

    Structures assigned to Seismic Design Category C shall conform to the requirements of this section.

    R301.2.2.2.1 Weights of materials.

    Average dead loads shall not exceed 15 pounds per square foot (720 Pa) for the combined roof and ceiling assemblies (on a horizontal projection) or 10 pounds per square foot (480 Pa) for floor assemblies, except as further limited by Section R301.2.2. Dead loads for walls above grade shall not exceed:

    1. 1.Fifteen pounds per square foot (720 Pa) for exterior light-frame wood walls.

    2. 2.Fourteen pounds per square foot (670 Pa) for exterior light-frame cold-formed steel walls.

    3. 3.Ten pounds per square foot (480 Pa) for interior light-frame wood walls.

    4. 4.Five pounds per square foot (240 Pa) for interior light-frame cold-formed steel walls.

    5. 5.Eighty pounds per square foot (3830 Pa) for 8-inch-thick (203 mm) masonry walls.

    6. 6.Eighty-five pounds per square foot (4070 Pa) for 6-inch-thick (152 mm) concrete walls.

    7. 7.Ten pounds per square foot (480 Pa) for SIP walls.

    Exceptions:

    1. 1.Roof and ceiling dead loads not exceeding 25 pounds per square foot (1190 Pa) shall be permitted provided that the wall bracing amounts in Section R602.10.3 are increased in accordance with Table R602.10.3(4).

    2. 2.Light-frame walls with stone or masonry veneer shall be permitted in accordance with the provisions of Sections R702.1 and R703.

    3. 3.Fireplaces and chimneys shall be permitted in accordance with Chapter 10.

    R301.2.2.2.2 Stone and masonry veneer.

    Anchored stone and masonry veneer shall comply with the requirements of Sections R702.1 and R703.

    R301.2.2.2.3 Masonry construction.

    Masonry construction shall comply with the requirements of Section R606.12.

    R301.2.2.2.4 Concrete construction.

    Detached one- and two-family dwellings with exterior above-grade concrete walls shall comply with the requirements of Section R608, PCA 100 or shall be designed in accordance with ACI 318. Townhouses with above-grade exterior concrete walls shall comply with the requirements of PCA 100 or shall be designed in accordance with ACI 318.

    R301.2.2.2.5 Irregular buildings.

    The seismic provisions of this code shall not be used for irregular structures located in Seismic Design Categories C, D0, D1 and D2. Irregular portions of structures shall be designed in accordance with accepted engineering practice to the extent the irregular features affect the performance of the remaining structural system. Where the forces associated with the irregularity are resisted by a structural system designed in accordance with accepted engineering practice, design of the remainder of the building shall be permitted using the provisions of this code. A building or portion of a building shall be considered to be irregular where one or more of the following conditions occur:

    1. 1.Where exterior shear wall lines or braced wall panels are not in one plane vertically from the foundation to the uppermost story in which they are required.

      Exception: For wood light-frame construction, floors with cantilevers or setbacks not exceeding four times the nominal depth of the wood floor joists are permitted to support braced wall panels that are out of plane with braced wall panels below provided that:

      1. 1.Floor joists are nominal 2 inches by 10 inches (51 mm by 254 mm) or larger and spaced not more than 16 inches (406 mm) on center.

      2. 2.The ratio of the back span to the cantilever is not less than 2 to 1.

      3. 3.Floor joists at ends of braced wall panels are doubled.

      4. 4.For wood-frame construction, a continuous rim joist is connected to ends of cantilever joists. When spliced, the rim joists shall be spliced using a galvanized metal tie not less than 0.058 inch (1.5 mm) (16 gage) and 11/2 inches (38 mm) wide fastened with six 16d nails on each side of the splice or a block of the same size as the rim joist of sufficient length to fit securely between the joist space at which the splice occurs fastened with eight 16d nails on each side of the splice; and

      5. 5.Gravity loads carried at the end of cantilevered joists are limited to uniform wall and roof loads and the reactions from headers having a span of 8 feet (2438 mm) or less.

    2. 2.Where a section of floor or roof is not laterally supported by shear walls or braced wall lines on all edges.

      Exception: Portions of floors that do not support shear walls or braced wall panels above, or roofs, shall be permitted to extend not more than 6 feet (1829 mm) beyond a shear wall or braced wall line.

    3. 3.Where the end of a braced wall panel occurs over an opening in the wall below and ends at a horizontal distance greater than 1 foot (305 mm) from the edge of the opening. This provision is applicable to shear walls and braced wall panels offset in plane and to braced wall panels offset out of plane as permitted by the exception to Item 1.

      Exception: For wood light-frame wall construction, one end of a braced wall panel shall be permitted to extend more than 1 foot (305 mm) over an opening not more than 8 feet (2438 mm) in width in the wall below provided that the opening includes a header in accordance with the following:

      1. 1.The building width, loading condition and framing member species limitations of Table R602.7(1) shall apply; and

      2. 2.Not less than one 2 × 12 or two 2 × 10 for an opening not more than 4 feet (1219 mm) wide; or

      3. 3.Not less than two 2 × 12 or three 2 × 10 for an opening not more than 6 feet (1829 mm) in width; or

      4. 4.Not less than three 2 × 12 or four 2 × 10 for an opening not more than 8 feet (2438 mm) in width; and

      5. 5.The entire length of the braced wall panel does not occur over an opening in the wall below.

    4. 4.Where an opening in a floor or roof exceeds the lesser of 12 feet (3658 mm) or 50 percent of the least floor or roof dimension.

    5. 5.Where portions of a floor level are vertically offset.

      Exceptions:

      1. 1.Framing supported directly by continuous foundations at the perimeter of the building.

      2. 2.For wood light-frame construction, floors shall be permitted to be vertically offset when the floor framing is lapped or tied together as required by Section R502.6.1.

    6. 6.Where shear walls and braced wall lines do not occur in two perpendicular directions.

    7. 7.Where stories above grade plane partially or completely braced by wood wall framing in accordance with Section R602 or cold-formed steel wall framing in accordance with Section R603 include masonry or concrete construction. Where this irregularity applies, the entire story shall be designed in accordance with accepted engineering practice.

      Exception: Fireplaces, chimneys and masonry veneer as permitted by this code.

    R301.2.2.3 Seismic Design Categories D0, D1 and D2.

    Structures assigned to Seismic Design Categories D0, D1 and D2 shall conform to the requirements for Seismic Design Category C and the additional requirements of this section.

    R301.2.2.3.1 Height limitations.

    Wood-framed buildings shall be limited to three stories above grade plane or the limits given in Table R602.10.3(3). Cold-formed, steel-framed buildings shall be limited to less than or equal to three stories above grade plane in accordance with AISI S230. Mezzanines as defined in Section R202 that comply with Section R325 shall not be considered as stories. Structural insulated panel buildings shall be limited to two stories above grade plane.

    R301.2.2.3.2 Stone and masonry veneer.

    Anchored stone and masonry veneer shall comply with the requirements of Sections R702.1 and R703.

    R301.2.2.3.3 Masonry construction.

    Masonry construction in Seismic Design Categories D0 and D1 shall comply with the requirements of Section R606.12.1. Masonry construction in Seismic Design Category D2 shall comply with the requirements of Section R606.12.4.

    R301.2.2.3.4 Concrete construction.

    Buildings with exterior above-grade concrete walls shall comply with PCA 100 or shall be designed in accordance with ACI 318.

    R301.2.2.3.5 Cold-formed steel framing in Seismic Design Categories D0, D1 and D2.

    In Seismic Design Categories D0, D1 and D2 in addition to the requirements of this code, cold-formed steel framing shall comply with the requirements of AISI S230.

    R301.2.2.3.6 Masonry chimneys.

    Masonry chimneys shall be reinforced and anchored to the building in accordance with Sections R1003.3 and R1003.4.

    R301.2.2.3.7 Anchorage of water heaters.

    Water heaters shall be anchored against movement and overturning in accordance with Section M1307.2.

    R301.2.2.4 Seismic Design Category E.

    Buildings in Seismic Design Category E shall be designed to resist seismic loads in accordance with the International Building Code, except where the seismic design category is reclassified to a lower seismic design category in accordance with Section R301.2.2.1. Components of buildings not required to be designed to resist seismic loads shall be constructed in accordance with the provisions of this code.

    R301.2.3 Snow loads.

    Wood-framed construction, cold-formed, steel-framed construction and masonry and concrete construction, and structural insulated panel construction in regions with ground snow loads 70 pounds per square foot (3.35 kPa) or less, shall be in accordance with Chapters 5, 6 and 8. Buildings in regions with ground snow loads greater than 70 pounds per square foot (3.35 kPa) shall be designed in accordance with accepted engineering practice.

    R301.2.4 Floodplain construction.

    Buildings and structures constructed in whole or in part in flood hazard areas (including A or V Zones) as established in Table R301.2(1), and substantial improvement and restoration of substantial damage of buildings and structures in flood hazard areas, shall be designed and constructed in accordance with Section R322. Buildings and structures that are located in more than one flood hazard area shall comply with the provisions associated with the most restrictive flood hazard area. Buildings and structures located in whole or in part in identified floodways shall be designed and constructed in accordance with ASCE 24.

    R301.2.4.1 Alternative provisions.

    As an alternative to the requirements in Section R322, ASCE 24 is permitted subject to the limitations of this code and the limitations therein.

    R301.3 Story height.

    The wind and seismic provisions of this code shall apply to buildings with story heights not exceeding the following:

    1. 1.For wood wall framing, the story height shall not exceed 11 feet 7 inches (3531 mm) and the laterally unsupported bearing wall stud height permitted by Table R602.3(5).

    2. 2.For cold-formed steel wall framing, the story height shall be not more than 11 feet 7 inches (3531 mm) and the unsupported bearing wall stud height shall be not more than 10 feet (3048 mm).

    3. 3.For masonry walls, the story height shall be not more than 13 feet 7 inches (4140 mm) and the bearing wall clear height shall be not greater than 12 feet (3658 mm).

      Exception: An additional 8 feet (2438 mm) of bearing wall clear height is permitted for gable end walls.

    4. 4.For insulating concrete form walls, the maximum story height shall not exceed 11 feet 7 inches (3531 mm) and the maximum unsupported wall height per story as permitted by Section R608 tables shall not exceed 10 feet (3048 mm).

    5. 5.For structural insulated panel (SIP) walls, the story height shall be not greater than 11 feet 7 inches (3531 mm) and the bearing wall height per story as permitted by Section R610 tables shall not exceed 10 feet (3048 mm).

    Individual walls or wall studs shall be permitted to exceed these limits as permitted by Chapter 6 provisions, provided that story heights are not exceeded. An engineered design shall be provided for the wall or wall framing members where the limits of Chapter 6 are exceeded. Where the story height limits of this section are exceeded, the design of the building, or the noncompliant portions thereof, to resist wind and seismic loads shall be in accordance with the International Building Code.

    R301.4 Dead load.

    The actual weights of materials and construction shall be used for determining dead load with consideration for the dead load of fixed service equipment.

    R301.5 Live load.

    The minimum uniformly distributed live load shall be as provided in Table R301.5.

    TABLE R301.5

    MINIMUM UNIFORMLY DISTRIBUTED LIVE LOADS (in pounds per square foot)

    USELIVE LOAD
    Uninhabitable attics without storageb10
    Uninhabitable attics with limited storageb, g20
    Habitable attics and attics served with fixed stairs30
    Balconies (exterior) and deckse40
    Fire escapes40
    Guards and handrailsd200h
    Guard in-fill componentsf50h
    Passenger vehicle garagesa50a
    Rooms other than sleeping rooms40
    Sleeping rooms30
    Stairs40c

    For SI: 1 pound per square foot = 0.0479 kPa, 1 square inch = 645 mm2, 1 pound = 4.45 N.

    1. a.Elevated garage floors shall be capable of supporting a 2,000-pound load applied over a 20-square-inch area.

    2. b.Uninhabitable attics without storage are those where the clear height between joists and rafters is not more than 42 inches, or where there are not two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses. This live load need not be assumed to act concurrently with any other live load requirements.

    3. c.Individual stair treads shall be designed for the uniformly distributed live load or a 300-pound concentrated load acting over an area of 4 square inches, whichever produces the greater stresses.

    4. d.A single concentrated load applied in any direction at any point along the top.

    5. e.See Section R507.1 for decks attached to exterior walls.

    6. f.Guard in-fill components (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds on an area equal to 1 square foot. This load need not be assumed to act concurrently with any other live load requirement.

    7. g.Uninhabitable attics with limited storage are those where the clear height between joists and rafters is not greater than 42 inches, or where there are two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses.

      The live load need only be applied to those portions of the joists or truss bottom chords where all of the following conditions are met:

      1. 1.The attic area is accessible from an opening not less than 20 inches in width by 30 inches in length that is located where the clear height in the attic is not less than 30 inches.

      2. 2.The slopes of the joists or truss bottom chords are not greater than 2 inches vertical to 12 units horizontal.

      3. 3.Required insulation depth is less than the joist or truss bottom chord member depth.

      The remaining portions of the joists or truss bottom chords shall be designed for a uniformly distributed concurrent live load of not less than 10 pounds per square foot.

    8. h.Glazing used in handrail assemblies and guards shall be designed with a safety factor of 4. The safety factor shall be applied to each of the concentrated loads applied to the top of the rail, and to the load on the in-fill components. These loads shall be determined independent of one another, and loads are assumed not to occur with any other live load.

    R301.6 Roof load.

    The roof shall be designed for the live load indicated in Table R301.6 or the snow load indicated in Table R301.2(1), whichever is greater.

    TABLE R301.6

    MINIMUM ROOF LIVE LOADS IN POUNDS-FORCE PER SQUARE FOOT OF HORIZONTAL PROJECTION

    ROOF SLOPETRIBUTARY LOADED AREA INSQUARE FEET FOR ANYSTRUCTURAL MEMBER
    0 to 200201 to 600Over 600
    Flat or rise less than 4 inches perfoot (1:3)201612
    Rise 4 inches per foot (1:3) toless than 12 inches per foot (1:1)161412
    Rise 12 inches per foot (1:1)and greater121212

    For SI: 1 square foot = 0.0929 m2, 1 pound per square foot = 0.0479 kPa, 1 inch per foot = 83.3 mm/m.

    R301.7 Deflection.

    The allowable deflection of any structural member under the live load listed in Sections R301.5 and R301.6 or wind loads determined by Section R301.2.1 shall not exceed the values in Table R301.7.

    TABLE R301.7

    ALLOWABLE DEFLECTION OF STRUCTURAL MEMBERSb, c

    STRUCTURAL MEMBERALLOWABLEDEFLECTION
    Rafters having slopes greater than 3:12 withfinished ceiling not attached to raftersL/180
    Interior walls and partitionsH/180
    FloorsL/360
    Ceilings with brittle finishes (including plasterand stucco)L/360
    Ceilings with flexible finishes (including gypsumboard)L/240
    All other structural membersL/240
    Exterior walls—wind loadsa with plaster orstucco finishH/360
    Exterior walls—wind loadsa with other brittlefinishesH/240
    Exterior walls—wind loadsa with flexible finishesH/120d
    Lintels supporting masonry veneer wallseL/600

    Note: L = span length, H = span height.

    1. a.For the purpose of the determining deflection limits herein, the wind load shall be permitted to be taken as 0.7 times the component and cladding (ASD) loads obtained from Table R301.2(2).

    2. bFor cantilever members, L shall be taken as twice the length of the cantilever.

    3. c.For aluminum structural members or panels used in roofs or walls of sunroom additions or patio covers, not supporting edge of glass or sandwich panels, the total load deflection shall not exceed L/60. For continuous aluminum structural members supporting edge of glass, the total load deflection shall not exceed L/175 for each glass lite or L/60 for the entire length of the member, whichever is more stringent. For sandwich panels used in roofs or walls of sunroom additions or patio covers, the total load deflection shall not exceed L/120.

    4. d.Deflection for exterior walls with interior gypsum board finish shall be limited to an allowable deflection of H/180.

    5. e.Refer to Section R703.8.2.

    R301.8 Nominal sizes.

    For the purposes of this code, dimensions of lumber specified shall be deemed to be nominal dimensions unless specifically designated as actual dimensions.

    SECTIONR302
    FIRE-RESISTANT CONSTRUCTION  

    R302.1 Exterior walls.

    Construction, projections, openings and penetrations of exterior walls of dwellings and accessory buildings shall comply with Table R302.1(1); or dwellings equipped throughout with an automatic sprinkler system installed in accordance with Section P2904 shall comply with Table R302.1(2).

    Exceptions:

    1. 1.Walls, projections, openings or penetrations in walls perpendicular to the line used to determine the fire separation distance.

    2. 2.Walls of dwellings and accessory structures located on the same lot.

    3. 3.Detached tool sheds and storage sheds, playhouses and similar structures exempted from permits are not required to provide wall protection based on location on the lot. Projections beyond the exterior wall shall not extend over the lot line.

    4. 4.Detached garages accessory to a dwelling located within 2 feet (610 mm) of a lot line are permitted to have roof eave projections not exceeding 4 inches (102 mm).

    5. 5.Foundation vents installed in compliance with this code are permitted.

    TABLE R302.1(1)

    EXTERIOR WALLS

    EXTERIOR WALL ELEMENTMINIMUMFIRE-RESISTANCE RATINGMINIMUM FIRESEPARATION DISTANCE
    WallsFire-resistance rated1 hour—tested in accordance with ASTM E 119or UL 263 with exposure from both sides< 5 feet
    Not fire-resistance rated0 hours≥ 5 feet
    ProjectionsNot allowedN/A< 2 feet
    Fire-resistance rated1 hour on the undersidea, b≥ 2 feet to < 5 feet
    Not fire-resistance rated0 hours≥ 5 feet
    Openings in wallsNot allowedN/A< 3 feet
    25% maximum of wall area0 hours3 feet
    Unlimited0 hours5 feet
    PenetrationsAllComply with Section R302.4< 3 feet
    None required3 feet
    For SI: 1 foot = 304.8 mm.

    N/A = Not Applicable.

    1. a.Roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave if fireblocking is provided from the wall top plate to the underside of the roof sheathing.

    2. b.Roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave provided that gable vent openings are not installed.

    TABLE R302.1(2)

    EXTERIOR WALLS—DWELLINGS WITH FIRE SPRINKLERS

    EXTERIOR WALL ELEMENTMINIMUMFIRE-RESISTANCE RATINGMINIMUM FIRESEPARATION DISTANCE
    WallsFire-resistance rated1 hour—tested in accordance with ASTM E 119 or UL 263 with exposure from the outside0 feet
    Not fire-resistance rated0 hours3 feeta
    ProjectionsNot allowedN/A< 2 feet
    Fire-resistance rated1 hour on the undersideb, c2 feeta
    Not fire-resistance rated0 hours3 feet
    Openings in wallsNot allowedN/A< 3 feet
    Unlimited0 hours3 feeta
    PenetrationsAllComply with Section R302.4< 3 feet
    None required3 feeta

    For SI: 1 foot = 304.8 mm.

    N/A = Not Applicable

    1. a.For residential subdivisions where all dwellings are equipped throughout with an automatic sprinkler system installed in accordance with Section P2904, the fire separation distance for nonrated exterior walls and rated projections shall be permitted to be reduced to 0 feet, and unlimited unprotected openings and penetrations shall be permitted, where the adjoining lot provides an open setback yard that is 6 feet or more in width on the opposite side of the property line.

    2. b.The roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave if fireblocking is provided from the wall top plate to the underside of the roof sheathing.

    3. c.The roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave provided that gable vent openings are not installed.

    R302.2 Townhouses.

    Common walls separating townhouses shall be assigned a fire-resistance rating in accordance with Section R302.2, Item 1 or 2. The common wall shared by two townhouses shall be constructed without plumbing or mechanical equipment, ducts or vents in the cavity of the common wall. The wall shall be rated for fire exposure from both sides and shall extend to and be tight against exterior walls and the underside of the roof sheathing. Electrical installations shall be in accordance with Chapters 34 through 43. Penetrations of the membrane of common walls for electrical outlet boxes shall be in accordance with Section R302.4.

    1. 1.Where a fire sprinkler system in accordance with Section P2904 is provided, the common wall shall be not less than a 1-hour fire-resistance-rated wall assembly tested in accordance with ASTM E 119 or UL 263.

    2. 2.Where a fire sprinkler system in accordance with Section P2904 is not provided, the common wall shall be not less than a 2-hour fire-resistance-rated wall assembly tested in accordance with ASTM E 119 or UL 263.

    R302.2.1 Continuity.

    The fire-resistance-rated wall or assembly separating townhouses shall be continuous from the foundation to the underside of the roof sheathing, deck or slab. The fire-resistance rating shall extend the full length of the wall or assembly, including wall extensions through and separating attached enclosed accessory structures.

    R302.2.2 Parapets for townhouses.

    Parapets constructed in accordance with Section R302.2.3 shall be constructed for townhouses as an extension of exterior walls or common walls in accordance with the following:

    1. 1.Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than 30 inches (762 mm) above the roof surfaces.

    2. 2.Where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is not more than 30 inches (762 mm) above the lower roof, the parapet shall extend not less than 30 inches (762 mm) above the lower roof surface.

      Exception: A parapet is not required in the preceding two cases where the roof covering complies with a minimum Class C rating as tested in accordance with ASTM E 108 or UL 790 and the roof decking or sheathing is of noncombustible materials or approved fire-retardant-treated wood for a distance of 4 feet (1219 mm) on each side of the wall or walls, or one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing, supported by not less than nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a distance of not less than 4 feet (1219 mm) on each side of the wall or walls and any openings or penetrations in the roof are not within 4 feet (1219 mm) of the common walls.

    3. 3.A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than 30 inches (762 mm) above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall have not less than a 1-hour fire-resistance rating. The wall shall be rated for exposure from both sides.

    R302.2.3 Parapet construction.

    Parapets shall have the same fire-resistance rating as that required for the supporting wall or walls. On any side adjacent to a roof surface, the parapet shall have noncombustible faces for the uppermost 18 inches (457 mm), to include counterflashing and coping materials. Where the roof slopes toward a parapet at slopes greater than 2 units vertical in 12 units horizontal (16.7-percent slope), the parapet shall extend to the same height as any portion of the roof within a distance of 3 feet (914 mm), and the height shall be not less than 30 inches (762 mm).

    R302.2.4 Structural independence.

    Each individual townhouse shall be structurally independent.

    Exceptions:

    1. 1.Foundations supporting exterior walls or common walls.

    2. 2.Structural roof and wall sheathing from each unit fastened to the common wall framing.

    3. 3.Nonstructural wall and roof coverings.

    4. 4.Flashing at termination of roof covering over common wall.

    5. 5.Townhouses separated by a common wall as provided in Section R302.2, Item 1 or 2.

    R302.3 Two-family dwellings.

    Dwelling units in two-family dwellings shall be separated from each other by wall and floor assemblies having not less than a 1-hour fire-resistance rating where tested in accordance with ASTM E 119 or UL 263. Fire-resistance-rated floor/ceiling and wall assemblies shall extend to and be tight against the exterior wall, and wall assemblies shall extend from the foundation to the underside of the roof sheathing.

    Exceptions:

    1. 1.A fire-resistance rating of 1/2 hour shall be permitted in buildings equipped throughout with an automatic sprinkler system installed in accordance with NFPA 13.

    2. 2.Wall assemblies need not extend through attic spaces where the ceiling is protected by not less than 5/8-inch (15.9 mm) Type X gypsum board, an attic draft stop constructed as specified in Section R302.12.1 is provided above and along the wall assembly separating the dwellings and the structural framing supporting the ceiling is protected by not less than 1/2-inch (12.7 mm) gypsum board or equivalent.

    R302.3.1 Supporting construction.

    Where floor assemblies are required to be fire-resistance rated by Section R302.3, the supporting construction of such assemblies shall have an equal or greater fire-resistance rating.

    R302.4 Dwelling unit rated penetrations.

    Penetrations of wall or floor-ceiling assemblies required to be fire-resistance rated in accordance with Section R302.2 or R302.3 shall be protected in accordance with this section.

    R302.4.1 Through penetrations.

    Through penetrations of fire-resistance-rated wall or floor assemblies shall comply with Section R302.4.1.1 or R302.4.1.2.

    Exception: Where the penetrating items are steel, ferrous or copper pipes, tubes or conduits, the annular space shall be protected as follows:

    1. 1.In concrete or masonry wall or floor assemblies, concrete, grout or mortar shall be permitted where installed to the full thickness of the wall or floor assembly or the thickness required to maintain the fire-resistance rating, provided that both of the following are complied with:

      1. 1.1.The nominal diameter of the penetrating item is not more than 6 inches (152 mm).

      2. 1.2.The area of the opening through the wall does not exceed 144 square inches (92 900 mm2).

    2. 2.The material used to fill the annular space shall prevent the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E 119 or UL 263 time temperature fire conditions under a positive pressure differential of not less than 0.01 inch of water (3 Pa) at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated.

    R302.4.1.1 Fire-resistance-rated assembly.

    Penetrations shall be installed as tested in the approved fire-resistance-rated assembly.

    R302.4.1.2 Penetration firestop system.

    Penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814 or UL 1479, with a positive pressure differential of not less than 0.01 inch of water (3 Pa) and shall have an F rating of not less than the required fire-resistance rating of the wall or floor-ceiling assembly penetrated.

    R302.4.2 Membrane penetrations.

    Membrane penetrations shall comply with Section R302.4.1. Where walls are required to have a fire-resistance rating, recessed fixtures shall be installed so that the required fire-resistance rating will not be reduced.

    Exceptions:

    1. 1.Membrane penetrations of not more than 2-hour fire-resistance-rated walls and partitions by steel electrical boxes that do not exceed 16 square inches (0.0103 m2) in area provided that the aggregate area of the openings through the membrane does not exceed 100 square inches (0.0645 m2) in any 100 square feet (9.29 m2) of wall area. The annular space between the wall membrane and the box shall not exceed 1/8 inch (3.1 mm). Such boxes on opposite sides of the wall shall be separated by one of the following:

      1. 1.1.By a horizontal distance of not less than 24 inches (610 mm) where the wall or partition is constructed with individual noncommunicating stud cavities.

      2. 1.2.By a horizontal distance of not less than the depth of the wall cavity where the wall cavity is filled with cellulose loose-fill, rockwool or slag mineral wool insulation.

      3. 1.3.By solid fireblocking in accordance with Section R302.11.

      4. 1.4.By protecting both boxes with listed putty pads.

      5. 1.5.By other listed materials and methods.

    2. 2.Membrane penetrations by listed electrical boxes of any materials provided that the boxes have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. The annular space between the wall membrane and the box shall not exceed 1/8 inch (3.1 mm) unless listed otherwise. Such boxes on opposite sides of the wall shall be separated by one of the following:

      1. 2.1.By the horizontal distance specified in the listing of the electrical boxes.

      2. 2.2.By solid fireblocking in accordance with Section R302.11.

      3. 2.3.By protecting both boxes with listed putty pads.

      4. 2.4.By other listed materials and methods.

    3. 3.The annular space created by the penetration of a fire sprinkler provided that it is covered by a metal escutcheon plate.

    R302.5 Dwelling-garage opening and penetration protection.

    Openings and penetrations through the walls or ceilings separating the dwelling from the garage shall be in accordance with Sections R302.5.1 through R302.5.3.

    R302.5.1 Opening protection.

    Openings from a private garage directly into a room used for sleeping purposes shall not be permitted. Other openings between the garage and residence shall be equipped with solid wood doors not less than 13/8 inches (35 mm) in thickness, solid or honeycomb-core steel doors not less than 13/8 inches (35 mm) thick, or 20-minute fire-rated doors, equipped with a self-closing device.

    R302.5.2 Duct penetration.

    Ducts in the garage and ducts penetrating the walls or ceilings separating the dwelling from the garage shall be constructed of a minimum No. 26 gage (0.48 mm) sheet steel or other approved material and shall not have openings into the garage.

    R302.5.3 Other penetrations.

    Penetrations through the separation required in Section R302.6 shall be protected as required by Section R302.11, Item 4.

    R302.6 Dwelling-garage fire separation.

    The garage shall be separated as required by Table R302.6. Openings in garage walls shall comply with Section R302.5. Attachment of gypsum board shall comply with Table R702.3.5. The wall separation provisions of Table R302.6 shall not apply to garage walls that are perpendicular to the adjacent dwelling unit wall.

    TABLE R302.6

    DWELLING-GARAGE SEPARATION

    SEPARATIONMATERIAL
    From the residence and atticsNot less than 1/2-inch gypsum board or equivalent applied to thegarage side
    From habitable rooms above the garageNot less than 5/8-inch Type X gypsum board or equivalent
    Structure(s) supporting floor/ceiling assemblies used for separationrequired by this sectionNot less than 1/2-inch gypsum board or equivalent
    Garages located less than 3 feet from a dwelling unit on the same lotNot less than 1/2-inch gypsum board or equivalent applied to the interiorside of exterior walls that are within this area

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

    R302.7 Under-stair protection.

    Enclosed accessible space under stairs shall have walls, under-stair surface and any soffits protected on the enclosed side with 1/2-inch (12.7 mm) gypsum board.

    R302.8 Foam plastics.

    For requirements for foam plastics, see Section R316.

    R302.9 Flame spread index and smoke-developed index for wall and ceiling finishes.

    Flame spread and smoke developed indexes for wall and ceiling finishes shall be in accordance with Sections R302.9.1 through R302.9.4.

    R302.9.1 Flame spread index.

    Wall and ceiling finishes shall have a flame spread index of not greater than 200.

    Exception: Flame spread index requirements for finishes shall not apply to trim defined as picture molds, chair rails, baseboards and handrails; to doors and windows or their frames; or to materials that are less than 1/28 inch (0.91 mm) in thickness cemented to the surface of walls or ceilings if these materials exhibit flame spread index values not greater than those of paper of this thickness cemented to a noncombustible backing.

    R302.9.2 Smoke-developed index.

    Wall and ceiling finishes shall have a smoke-developed index of not greater than 450.

    R302.9.3 Testing.

    Tests shall be made in accordance with ASTM E 84 or UL 723.

    R302.9.4 Alternative test method.

    As an alternative to having a flame spread index of not greater than 200 and a smoke-developed index of not greater than 450 where tested in accordance with ASTM E 84 or UL 723, wall and ceiling finishes shall be permitted to be tested in accordance with NFPA 286. Materials tested in accordance with NFPA 286 shall meet the following criteria:

    • The interior finish shall comply with the following:

      1. 1.During the 40 kW exposure, flames shall not spread to the ceiling.

      2. 2.The flame shall not spread to the outer extremity of the sample on any wall or ceiling.

      3. 3.Flashover, as defined in NFPA 286, shall not occur.

      4. 4.The peak heat release rate throughout the test shall not exceed 800 kW.

      5. 5.The total smoke released throughout the test shall not exceed 1,000 m2.

    R302.10 Flame spread index and smoke-developed index for insulation.

    Flame spread and smoke-developed index for insulation shall be in accordance with Sections R302.10.1 through R302.10.5.

    R302.10.1 Insulation.

    Insulation materials, including facings, such as vapor retarders and vapor-permeable membranes installed within floor-ceiling assemblies, roof-ceiling assemblies, wall assemblies, crawl spaces and attics shall have a flame spread index not to exceed 25 with an accompanying smoke-developed index not to exceed 450 where tested in accordance with ASTM E 84 or UL 723.

    Exceptions:

    1. 1.Where such materials are installed in concealed spaces, the flame spread index and smoke-developed index limitations do not apply to the facings, provided that the facing is installed in substantial contact with the unexposed surface of the ceiling, floor or wall finish.

    2. 2.Cellulose fiber loose-fill insulation, that is not spray applied, complying with the requirements of Section R302.10.3, shall not be required to meet the smoke-developed index of not more than 450 and shall be required to meet a smoke-developed index of not more than 450 where tested in accordance with CAN/ULC S102.2.

    3. 3.Foam plastic insulation shall comply with Section R316.

    R302.10.2 Loose-fill insulation.

    Loose-fill insulation materials that cannot be mounted in the ASTM E 84 or UL 723 apparatus without a screen or artificial supports shall comply with the flame spread and smoke-developed limits of Section R302.10.1 where tested in accordance with CAN/ULC S102.2.

    Exception: Cellulosic fiber loose-fill insulation shall not be required to be tested in accordance with CAN/ ULC S102.2, provided such insulation complies with the requirements of Sections R302.10.1 and R302.10.3.

    R302.10.3 Cellulosic fiber loose-fill insulation.

    Cellulosic fiber loose-fill insulation shall comply with CPSC 16 CFR, Parts 1209 and 1404. Each package of such insulating material shall be clearly labeled in accordance with CPSC 16 CFR, Parts 1209 and 1404.

    R302.10.4 Exposed attic insulation.

    Exposed insulation materials installed on attic floors shall have a critical radiant flux not less than 0.12 watt per square centimeter.

    R302.10.5 Testing.

    Tests for critical radiant flux shall be made in accordance with ASTM E 970.

    R302.11 Fireblocking.

    In combustible construction, fire-blocking shall be provided to cut off both vertical and horizontal concealed draft openings and to form an effective fire barrier between stories, and between a top story and the roof space.

    Fireblocking shall be provided in wood-framed construction in the following locations:

    1. 1.In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs, as follows:

      1. 1.1.Vertically at the ceiling and floor levels.

      2. 1.2.Horizontally at intervals not exceeding 10 feet (3048 mm).

    2. 2.At interconnections between concealed vertical and horizontal spaces such as occur at soffits, drop ceilings and cove ceilings.

    3. 3.In concealed spaces between stair stringers at the top and bottom of the run. Enclosed spaces under stairs shall comply with Section R302.7.

    4. 4.At openings around vents, pipes, ducts, cables and wires at ceiling and floor level, with an approved material to resist the free passage of flame and products of combustion. The material filling this annular space shall not be required to meet the ASTM E 136 requirements.

    5. 5.For the fireblocking of chimneys and fireplaces, see Section R1003.19.

    6. 6.Fireblocking of cornices of a two-family dwelling is required at the line of dwelling unit separation.

    R302.11.1 Fireblocking materials.

    Except as provided in Section R302.11, Item 4, fireblocking shall consist of the following materials.

    1. 1.Two-inch (51 mm) nominal lumber.

    2. 2.Two thicknesses of 1-inch (25.4 mm) nominal lumber with broken lap joints.

    3. 3.One thickness of 23/32-inch (18.3 mm) wood structural panels with joints backed by 23/32-inch (18.3 mm) wood structural panels.

    4. 4.One thickness of 3/4-inch (19.1 mm) particleboard with joints backed by 3/4-inch (19.1 mm) particle-board.

    5. 5.One-half-inch (12.7 mm) gypsum board.

    6. 6.One-quarter-inch (6.4 mm) cement-based millboard.

    7. 7.Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place.

    8. 8.Cellulose insulation installed as tested in accordance with ASTM E 119 or UL 263, for the specific application.

    R302.11.1.1 Batts or blankets of mineral or glass fiber.

    Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10-foot (3048 mm) horizontal fireblocking in walls constructed using parallel rows of studs or staggered studs.

    R302.11.1.2 Unfaced fiberglass.

    Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a height of not less than 16 inches (406 mm) measured vertically. Where piping, conduit or similar obstructions are encountered, the insulation shall be packed tightly around the obstruction.

    R302.11.1.3 Loose-fill insulation material.

    Loose-fill insulation material shall not be used as a fireblock unless specifically tested in the form and manner intended for use to demonstrate its ability to remain in place and to retard the spread of fire and hot gases.

    R302.11.2 Fireblocking integrity.

    The integrity of fire-blocks shall be maintained.

    R302.12 Draftstopping.

    In combustible construction where there is usable space both above and below the concealed space of a floor-ceiling assembly, draftstops shall be installed so that the area of the concealed space does not exceed 1,000 square feet (92.9 m2). Draftstopping shall divide the concealed space into approximately equal areas. Where the assembly is enclosed by a floor membrane above and a ceiling membrane below, draftstopping shall be provided in floor-ceiling assemblies under the following circumstances:

    1. 1.Ceiling is suspended under the floor framing.

    2. 2.Floor framing is constructed of truss-type open-web or perforated members.

    R302.12.1 Materials.

    Draftstopping materials shall be not less than 1/2-inch (12.7 mm) gypsum board, 3/8-inch (9.5 mm) wood structural panels or other approved materials adequately supported. Draftstopping shall be installed parallel to the floor framing members unless otherwise approved by the building official. The integrity of the draftstops shall be maintained.

    R302.13 Fire protection of floors.

    Floor assemblies that are not required elsewhere in this code to be fire-resistance rated, shall be provided with a 1/2-inch (12.7 mm) gypsum wallboard membrane, 5/8-inch (16 mm) wood structural panel membrane, or equivalent on the underside of the floor framing member. Penetrations or openings for ducts, vents, electrical outlets, lighting, devices, luminaires, wires, speakers, drainage, piping and similar openings or penetrations shall be permitted.

    Exceptions:

    1. 1.Floor assemblies located directly over a space protected by an automatic sprinkler system in accordance with Section P2904, NFPA 13D, or other approved equivalent sprinkler system.

    2. 2.Floor assemblies located directly over a crawl space not intended for storage or fuel-fired appliances.

    3. 3.Portions of floor assemblies shall be permitted to be unprotected where complying with the following:

      1. 3.1.The aggregate area of the unprotected portions does not exceed 80 square feet (7.4 m2) per story

      2. 3.2.Fireblocking in accordance with Section R302.11.1 is installed along the perimeter of the unprotected portion to separate the unprotected portion from the remainder of the floor assembly.

    4. 4.Wood floor assemblies using dimension lumber or structural composite lumber equal to or greater than 2-inch by 10-inch (50.8 mm by 254 mm) nominal dimension, or other approved floor assemblies demonstrating equivalent fire performance.

    R302.14 Combustible insulation clearance.

    Combustible insulation shall be separated not less than 3 inches (76 mm) from recessed luminaires, fan motors and other heat-producing devices.

    Exception: Where heat-producing devices are listed for lesser clearances, combustible insulation complying with the listing requirements shall be separated in accordance with the conditions stipulated in the listing.

    Recessed luminaires installed in the building thermal envelope shall meet the requirements of Section N1102.4.5 of this code.

    SECTIONR303
    LIGHT, VENTILATION AND HEATING

    R303.1 Habitable rooms.

    Habitable rooms shall have an aggregate glazing area of not less than 8 percent of the floor area of such rooms. Natural ventilation shall be through windows, skylights, doors, louvers or other approved openings to the outdoor air. Such openings shall be provided with ready access or shall otherwise be readily controllable by the building occupants. The openable area to the outdoors shall be not less than 4 percent of the floor area being ventilated.

    Exceptions:

    1. 1.The glazed areas need not be openable where the opening is not required by Section R310 and a whole-house mechanical ventilation system is installed in accordance with Section M1507.

    2. 2.The glazed areas need not be installed in rooms where Exception 1 is satisfied and artificial light is provided that is capable of producing an average illumination of 6 footcandles (65 lux) over the area of the room at a height of 30 inches (762 mm) above the floor level.

    3. 3.Use of sunroom and patio covers, as defined in Section R202, shall be permitted for natural ventilation if in excess of 40 percent of the exterior sunroom walls are open, or are enclosed only by insect screening.

    R303.2 Adjoining rooms.

    For the purpose of determining light and ventilation requirements, any room shall be considered to be a portion of an adjoining room where not less than one-half of the area of the common wall is open and unobstructed and provides an opening of not less than one-tenth of the floor area of the interior room and not less than 25 square feet (2.3 m2).

    Exception: Openings required for light or ventilation shall be permitted to open into a sunroom with thermal isolation or a patio cover, provided that there is an openable area between the adjoining room and the sunroom or patio cover of not less than one-tenth of the floor area of the interior room and not less than 20 square feet (2 m2). The minimum openable area to the outdoors shall be based upon the total floor area being ventilated.

    R303.3 Bathrooms.

    Bathrooms, water closet compartments and other similar rooms shall be provided with aggregate glazing area in windows of not less than 3 square feet (0.3 m2), one-half of which must be openable.

    Exception: The glazed areas shall not be required where artificial light and a local exhaust system are provided. The minimum local exhaust rates shall be determined in accordance with Section M1507. Exhaust air from the space shall be exhausted directly to the outdoors.

    R303.4 Mechanical ventilation.

    Where the air infiltration rate of a dwelling unit is 5 air changes per hour or less where tested with a blower door at a pressure of 0.2 inch w.c (50 Pa) in accordance with Section N1102.4.1.2, the dwelling unit shall be provided with whole-house mechanical ventilation in accordance with Section M1507.3.

    R303.5 Opening location.

    Outdoor intake and exhaust openings shall be located in accordance with Sections R303.5.1 and R303.5.2.

    R303.5.1 Intake openings.

    Mechanical and gravity outdoor air intake openings shall be located not less than 10 feet (3048 mm) from any hazardous or noxious contaminant, such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks.

    For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious.

    Exceptions:

    1. 1.The 10-foot (3048 mm) separation is not required where the intake opening is located 3 feet (914 mm) or greater below the contaminant source.

    2. 2.Vents and chimneys serving fuel-burning appliances shall be terminated in accordance with the applicable provisions of Chapters 18 and 24.

    3. 3.Clothes dryer exhaust ducts shall be terminated in accordance with Section M1502.3.

    R303.5.2 Exhaust openings.

    Exhaust air shall not be directed onto walkways.

    R303.6 Outside opening protection.

    Air exhaust and intake openings that terminate outdoors shall be protected with corrosion-resistant screens, louvers or grilles having an opening size of not less than 1/4 inch (6 mm) and a maximum opening size of 1/2 inch (13 mm), in any dimension. Openings shall be protected against local weather conditions. Outdoor air exhaust and intake openings shall meet the provisions for exterior wall opening protectives in accordance with this code.

    R303.7 Interior stairway illumination.

    Interior stairways shall be provided with an artificial light source to illuminate the landings and treads. The light source shall be capable of illuminating treads and landings to levels of not less than 1 foot-candle (11 lux) as measured at the center of treads and landings. There shall be a wall switch at each floor level to control the light source where the stairway has six or more risers.

    Exception: A switch is not required where remote, central or automatic control of lighting is provided.

    R303.8 Exterior stairway illumination.

    Exterior stairways shall be provided with an artificial light source located at the top landing of the stairway. Exterior stairways providing access to a basement from the outdoor grade level shall be provided with an artificial light source located at the bottom landing of the stairway.

    R303.9 Required glazed openings.

    Required glazed openings shall open directly onto a street or public alley, or a yard or court located on the same lot as the building.

    Exceptions:

    1. 1.Required glazed openings that face into a roofed porch where the porch abuts a street, yard or court and the longer side of the porch is not less than 65 percent unobstructed and the ceiling height is not less than 7 feet (2134 mm).

    2. 2.Eave projections shall not be considered as obstructing the clear open space of a yard or court.

    3. 3.Required glazed openings that face into the area under a deck, balcony, bay or floor cantilever where a clear vertical space not less than 36 inches (914 mm) in height is provided.

    R303.9.1 Sunroom additions.

    Required glazed openings shall be permitted to open into sunroom additions or patio covers that abut a street, yard or court if in excess of 40 percent of the exterior sunroom walls are open, or are enclosed only by insect screening, and the ceiling height of the sunroom is not less than 7 feet (2134 mm).

    R303.10 Required heating.

    Where the winter design temperature in Table R301.2(1) is below 60°F (16°C), every dwelling unit shall be provided with heating facilities capable of maintaining a room temperature of not less than 68°F (20°C) at a point 3 feet (914 mm) above the floor and 2 feet (610 mm) from exterior walls in habitable rooms at the design temperature. The installation of one or more portable space heaters shall not be used to achieve compliance with this section.

    SECTIONR304
    MINIMUM ROOM AREAS  

    R304.1 Minimum area.

    Habitable rooms shall have a floor area of not less than 70 square feet (6.5 m2).

    Exception: Kitchens.

    R304.2 Minimum dimensions.

    Habitable rooms shall be not less than 7 feet (2134 mm) in any horizontal dimension.

    Exception: Kitchens.

    R304.3 Height effect on room area.

    Portions of a room with a sloping ceiling measuring less than 5 feet (1524 mm) or a furred ceiling measuring less than 7 feet (2134 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.

    SECTIONR305
    CEILING HEIGHT

    R305.1 Minimum height.

    Habitable space, hallways and portions of basements containing these spaces shall have a ceiling height of not less than 7 feet (2134 mm). Bathrooms, toilet rooms and laundry rooms shall have a ceiling height of not less than 6 feet 8 inches (2032 mm).

    Exceptions:

    1. 1.For rooms with sloped ceilings, the required floor area of the room shall have a ceiling height of not less than 5 feet (1524 mm) and not less than 50 percent of the required floor area shall have a ceiling height of not less than 7 feet (2134 mm).

    2. 2.The ceiling height above bathroom and toilet room fixtures shall be such that the fixture is capable of being used for its intended purpose. A shower or tub equipped with a showerhead shall have a ceiling height of not less than 6 feet 8 inches (2032 mm) above an area of not less than 30 inches (762 mm) by 30 inches (762 mm) at the showerhead.

    3. 3.Beams, girders, ducts or other obstructions in basements containing habitable space shall be permitted to project to within 6 feet 4 inches (1931 mm) of the finished floor.

    R305.1.1 Basements.

    Portions of basements that do not contain habitable space or hallways shall have a ceiling height of not less than 6 feet 8 inches (2032 mm).

    Exception: At beams, girders, ducts or other obstructions, the ceiling height shall be not less than 6 feet 4 inches (1931 mm) from the finished floor.

    SECTIONR306
    SANITATION

    R306.1 Toilet facilities.

    Every dwelling unit shall be provided with a water closet, lavatory, and a bathtub or shower.

    R306.2 Kitchen.

    Each dwelling unit shall be provided with a kitchen area and every kitchen area shall be provided with a sink.

    R306.3 Sewage disposal.

    Plumbing fixtures shall be connected to a sanitary sewer or to an approved private sewage disposal system.

    R306.4 Water supply to fixtures.

    Plumbing fixtures shall be connected to an approved water supply. Kitchen sinks, lavatories, bathtubs, showers, bidets, laundry tubs and washing machine outlets shall be provided with hot and cold water.

    SECTIONR307
    TOILET, BATH AND SHOWER SPACES

    R307.1 Space required.

    Fixtures shall be spaced in accordance with Figure R307.1, and in accordance with the requirements of Section P2705.1.

    For SI: 1 inch = 25.4 mm.

    FIGURE R307.1

    MINIMUM FIXTURE CLEARANCES

    R307.2 Bathtub and shower spaces.

    Bathtub and shower floors and walls above bathtubs with installed shower heads and in shower compartments shall be finished with a nonabsorbent surface. Such wall surfaces shall extend to a height of not less than 6 feet (1829 mm) above the floor.

    SECTIONR308
    GLAZING  

    R308.1 Identification.

    Except as indicated in Section R308.1.1 each pane of glazing installed in hazardous locations as defined in Section R308.4 shall be provided with a manufacturer’s designation specifying who applied the designation, designating the type of glass and the safety glazing standard with which it complies, which is visible in the final installation. The designation shall be acid etched, sand-blasted, ceramic-fired, laser etched, embossed, or be of a type that once applied cannot be removed without being destroyed. A label shall be permitted in lieu of the manufacturer’s designation.

    Exceptions:

    1. 1.For other than tempered glass, manufacturer’s designations are not required provided that the building official approves the use of a certificate, affidavit or other evidence confirming compliance with this code.

    2. 2.Tempered spandrel glass is permitted to be identified by the manufacturer with a removable paper designation.

    R308.1.1 Identification of multiple assemblies.

    Multi-pane assemblies having individual panes not exceeding 1 square foot (0.09 m2) in exposed area shall have not less than one pane in the assembly identified in accordance with Section R308.1. Other panes in the assembly shall be labeledCPSC 16 CFR 1201” or “ANSI Z97.1” as appropriate.

    R308.2 Louvered windows or jalousies.

    Regular, float, wired or patterned glass in jalousies and louvered windows shall be not less than nominal 3/16 inch (5 mm) thick and not more than 48 inches (1219 mm) in length. Exposed glass edges shall be smooth.

    R308.2.1 Wired glass prohibited.

    Wired glass with wire exposed on longitudinal edges shall not be used in jalousies or louvered windows.

    R308.3 Human impact loads.

    Individual glazed areas, including glass mirrors in hazardous locations such as those indicated as defined in Section R308.4, shall pass the test requirements of Section R308.3.1.

    Exceptions:

    1. 1.Louvered windows and jalousies shall comply with Section R308.2.

    2. 2.Mirrors and other glass panels mounted or hung on a surface that provides a continuous backing support.

    3. 3.Glass unit masonry complying with Section R607.

    R308.3.1 Impact test.

    Where required by other sections of the code, glazing shall be tested in accordance with CPSC 16 CFR 1201. Glazing shall comply with the test criteria for Category II unless otherwise indicated in Table R308.3.1(1).

    Exception: Glazing not in doors or enclosures for hot tubs, whirlpools, saunas, steam rooms, bathtubs and showers shall be permitted to be tested in accordance with ANSI Z97.1. Glazing shall comply with the test criteria for Class A unless indicated in Table R308.3.1(2).

    TABLE R308.3.1(1)

    MINIMUM CATEGORY CLASSIFICATION OF GLAZING USING CPSC 16 CFR 1201

    EXPOSED SURFACEAREA OF ONE SIDEOF ONE LITEGLAZING INSTORM ORCOMBINATIONDOORS(Category Class)GLAZING INDOORS(Category Class)GLAZED PANELSREGULATED BYSECTION R308.4.3(Category Class)GLAZED PANELSREGULATED BYSECTION R308.4.2(Category Class)GLAZING INDOORS ANDENCLOSURESREGULATED BYSECTION 308.4.5(Category Class)SLIDING GLASSDOORS PATIO TYPE(Category Class)
    9 square feet or lessIINRIIIII
    More than 9 square feetIIIIIIIIIIII

    For SI: 1 square foot = 0.0929 m2.

    NR = “No Requirement.”

    TABLE R308.3.1(2)

    MINIMUM CATEGORY CLASSIFICATION OF GLAZING USING ANSI Z97.1.

    EXPOSED SURFACE AREAOF ONE SIDE OF ONE LITEGLAZED PANELS REGULATED BYSECTION R308.4.3(Category Class)GLAZED PANELS REGULATED BYSECTION R308.4.2.(Category Class)DOORS AND ENCLOSURES REGULATEDBY SECTION R308.4.5a(Category Class)
    9 square feet or lessNo requirementBA
    More than 9 square feetAAA

    For SI: 1 square foot = 0.0929 m2.

    1. a.Use is permitted only by the exception to Section R308.3.1.

    R308.4 Hazardous locations.

    The locations specified in Sections R308.4.1 through R308.4.7 shall be considered to be specific hazardous locations for the purposes of glazing.

    R308.4.1 Glazing in doors.

    Glazing in fixed and operable panels of swinging, sliding and bifold doors shall be considered to be a hazardous location.

    Exceptions:

    1. 1.Glazed openings of a size through which a 3-inch-diameter (76 mm) sphere is unable to pass.

    2. 2.Decorative glazing.

    R308.4.2 Glazing adjacent to doors.

    Glazing in an individual fixed or operable panel adjacent to a door shall be considered to be a hazardous location where the bottom exposed edge of the glazing is less than 60 inches (1524 mm) above the floor or walking surface and it meets either of the following conditions:

    1. 1.Where the glazing is within 24 inches (610 mm) of either side of the door in the plane of the door in a closed position.

    2. 2.Where the glazing is on a wall perpendicular to the plane of the door in a closed position and within 24 inches (610 mm) of the hinge side of an in-swinging door.

      Exceptions:

      1. 1.Decorative glazing.

      2. 2.Where there is an intervening wall or other permanent barrier between the door and the glazing.

      3. 3.Where access through the door is to a closet or storage area 3 feet (914 mm) or less in depth. Glazing in this application shall comply with Section R308.4.3.

      4. 4.Glazing that is adjacent to the fixed panel of patio doors.

    R308.4.3 Glazing in windows.

    Glazing in an individual fixed or operable panel that meets all of the following conditions shall be considered to be a hazardous location:

    1. 1.The exposed area of an individual pane is larger than 9 square feet (0.836 m2),

    2. 2.The bottom edge of the glazing is less than 18 inches (457 mm) above the floor,

    3. 3.The top edge of the glazing is more than 36 inches (914 mm) above the floor; and

    4. 4.One or more walking surfaces are within 36 inches (914 mm), measured horizontally and in a straight line, of the glazing.

      Exceptions:

      1. 1.Decorative glazing.

      2. 2.Where a horizontal rail is installed on the accessible side(s) of the glazing 34 to 38 inches (864 to 965 mm) above the walking surface. The rail shall be capable of withstanding a horizontal load of 50 pounds per linear foot (730 N/m) without contacting the glass and have a cross-sectional height of not less than 11/2 inches (38 mm).

      3. 3.Outboard panes in insulating glass units and other multiple glazed panels where the bottom edge of the glass is 25 feet (7620 mm) or more above grade, a roof, walking surfaces or other horizontal [within 45 degrees (0.79 rad) of horizontal] surface adjacent to the glass exterior.

    R308.4.4 Glazing in guards and railings.

    Glazing in guards and railings, including structural baluster panels and nonstructural in-fill panels, regardless of area or height above a walking surface shall be considered to be a hazardous location.

    R308.4.5 Glazing and wet surfaces.

    Glazing in walls, enclosures or fences containing or facing hot tubs, spas, whirlpools, saunas, steam rooms, bathtubs, showers and indoor or outdoor swimming pools where the bottom exposed edge of the glazing is less than 60 inches (1524 mm) measured vertically above any standing or walking surface shall be considered to be a hazardous location. This shall apply to single glazing and each pane in multiple glazing.

    Exception: Glazing that is more than 60 inches (1524 mm), measured horizontally and in a straight line, from the water’s edge of a bathtub, hot tub, spa, whirlpool or swimming pool or from the edge of a shower, sauna or steam room.

    R308.4.6 Glazing adjacent to stairs and ramps.

    Glazing where the bottom exposed edge of the glazing is less than 36 inches (914 mm) above the plane of the adjacent walking surface of stairways, landings between flights of stairs and ramps shall be considered to be a hazardous location.

    Exceptions:

    1. 1.Where a rail is installed on the accessible side(s) of the glazing 34 to 38 inches (864 to 965 mm) above the walking surface. The rail shall be capable of withstanding a horizontal load of 50 pounds per linear foot (730 N/m) without contacting the glass and have a cross-sectional height of not less than 11/2 inches (38 mm).

    2. 2.Glazing 36 inches (914 mm) or more measured horizontally from the walking surface.

    R308.4.7 Glazing adjacent to the bottom stair landing.

    Glazing adjacent to the landing at the bottom of a stairway where the glazing is less than 36 inches (914 mm) above the landing and within a 60-inch (1524 mm) horizontal arc less than 180 degrees from the bottom tread nosing shall be considered to be a hazardous location.

    Exception: The glazing is protected by a guard complying with Section R312 and the plane of the glass is more than 18 inches (457 mm) from the guard.

    FIGURE R308.4.7

    PROHIBITED GLAZING LOCATIONS AT BOTTOM STAIR LANDINGS

    R308.5 Site-built windows.

    Site-built windows shall comply with Section 2404 of the International Building Code.

    R308.6 Skylights and sloped glazing.

    Skylights and sloped glazing shall comply with the following sections.

    R308.6.1 Definitions.

    The following terms are defined in Chapter 2:

    • SKYLIGHT, UNIT.

    • SKYLIGHTS AND SLOPED GLAZING.

    • TUBULAR DAYLIGHTING DEVICE (TDD).

    R308.6.2 Materials.

    The following types of glazing shall be permitted to be used:

    1. 1.Laminated glass with not less than a 0.015-inch (0.38 mm) polyvinyl butyral interlayer for glass panes 16 square feet (1.5 m2) or less in area located such that the highest point of the glass is not more than 12 feet (3658 mm) above a walking surface or other accessible area; for higher or larger sizes, the interlayer thickness shall be not less than 0.030 inch (0.76 mm).

    2. 2.Fully tempered glass.

    3. 3.Heat-strengthened glass.

    4. 4.Wired glass.

    5. 5.Approved rigid plastics.

    R308.6.3 Screens, general.

    For fully tempered or heat-strengthened glass, a retaining screen meeting the requirements of Section R308.6.7 shall be installed below the glass, except for fully tempered glass that meets either condition listed in Section R308.6.5.

    R308.6.4 Screens with multiple glazing.

    Where the inboard pane is fully tempered, heat-strengthened or wired glass, a retaining screen meeting the requirements of Section R308.6.7 shall be installed below the glass, except for either condition listed in Section R308.6.5. Other panes in the multiple glazing shall be of any type listed in Section R308.6.2.

    R308.6.5 Screens not required.

    Screens shall not be required where fully tempered glass is used as single glazing or the inboard pane in multiple glazing and either of the following conditions are met:

    1. 1.Glass area 16 square feet (1.49 m2) or less. Highest point of glass not more than 12 feet (3658 mm) above a walking surface or other accessible area, nominal glass thickness not more than 3/16 inch (4.8 mm), and (for multiple glazing only) the other pane or panes fully tempered, laminated or wired glass.

    2. 2.Glass area greater than 16 square feet (1.49 m2). Glass sloped 30 degrees (0.52 rad) or less from vertical, and highest point of glass not more than 10 feet (3048 mm) above a walking surface or other accessible area.

    R308.6.6 Glass in greenhouses.

    Any glazing material is permitted to be installed without screening in the sloped areas of greenhouses, provided that the greenhouse height at the ridge does not exceed 20 feet (6096 mm) above grade.

    R308.6.7 Screen characteristics.

    The screen and its fastenings shall be capable of supporting twice the weight of the glazing, be firmly and substantially fastened to the framing members, and have a mesh opening of not more than 1 inch by 1 inch (25 mm by 25 mm).

    R308.6.8 Curbs for skylights.

    Unit skylights installed in a roof with a pitch flatter than three units vertical in 12 units horizontal (25-percent slope) shall be mounted on a curb extending not less than 4 inches (102 mm) above the plane of the roof unless otherwise specified in the manufacturer’s installation instructions.

    R308.6.9 Testing and labeling.

    Unit skylights and tubular daylighting devices shall be tested by an approved independent laboratory, and bear a label identifying manufacturer, performance grade rating and approved inspection agency to indicate compliance with the requirements of AAMA/WDMA/CSA 101/I.S.2/A440.

    R308.6.9.1 Comparative analysis for glass-glazed unit skylights.

    Structural wind load design pressures for glass-glazed unit skylights different than the size tested in accordance with Section R308.6.9 shall be permitted to be different than the design value of the tested unit where determined in accordance with one of the following comparative analysis methods:

    1. 1.Structural wind load design pressures for glass-glazed unit skylights smaller than the size tested in accordance with Section R308.6.9 shall be permitted to be higher than the design value of the tested unit provided that such higher pressures are determined by accepted engineering analysis. Components of the smaller unit shall be the same as those of the tested unit. Such calculated design pressures shall be validated by an additional test of the glass-glazed unit skylight having the highest allowable design pressure.

    2. 2.In accordance with WDMA I.S. 11.

    SECTIONR309
    GARAGES AND CARPORTS

    R309.1 Floor surface.

    Garage floor surfaces shall be of approved noncombustible material.

    The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway.

    R309.2 Carports.

    Carports shall be open on not less than two sides. Carport floor surfaces shall be of approved noncombustible material. Carports not open on two or more sides shall be considered to be a garage and shall comply with the provisions of this section for garages.

    Exception: Asphalt surfaces shall be permitted at ground level in carports.

    The area of floor used for parking of automobiles or other vehicles shall be sloped to facilitate the movement of liquids to a drain or toward the main vehicle entry doorway.

    R309.3 Flood hazard areas.

    For buildings located in flood hazard areas as established by Table R301.2(1), garage floors shall be:

    1. 1.Elevated to or above the design flood elevation as determined in accordance with Section R322; or

    2. 2.Located below the design flood elevation provided that the floors are at or above grade on not less than one side, are used solely for parking, building access or storage, meet the requirements of Section R322 and are otherwise constructed in accordance with this code.

    R309.4 Automatic garage door openers.

    Automatic garage door openers, if provided, shall be listed and labeled in accordance with UL 325.

    R309.5 Fire sprinklers.

    Private garages shall be protected by fire sprinklers where the garage wall has been designed based on Table R302.1(2), Footnote a. Sprinklers in garages shall be connected to an automatic sprinkler system that complies with Section P2904. Garage sprinklers shall be residential sprinklers or quick-response sprinklers, designed to provide a density of 0.05 gpm/ft2. Garage doors shall not be considered obstructions with respect to sprinkler placement.

    SECTIONR310
    EMERGENCY ESCAPE AND RESCUE OPENINGS

    R310.1 Emergency escape and rescue opening required.

    Basements, habitable attics and every sleeping room shall have not less than one operable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room. Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.

    Exception: Storm shelters and basements used only to house mechanical equipment not exceeding a total floor area of 200 square feet (18.58 m2).

    R310.1.1 Operational constraints and opening control devices.

    Emergency escape and rescue openings shall be operational from the inside of the room without the use of keys, tools or special knowledge. Window opening control devices complying with ASTM F 2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening.

    R310.2 Emergency escape and rescue openings.

    Emergency escape and rescue openings shall have minimum dimensions as specified in this section.

    R310.2.1 Minimum opening area.

    Emergency and escape rescue openings shall have a net clear opening of not less than 5.7 square feet (0.530 m2). The net clear opening dimensions required by this section shall be obtained by the normal operation of the emergency escape and rescue opening from the inside. The net clear height opening shall be not less than 24 inches (610 mm) and the net clear width shall be not less than 20 inches (508 mm).

    Exception: Grade floor or below grade openings shall have a net clear opening of not less than 5 square feet (0.465 m2).

    R310.2.2 Window sill height.

    Where a window is provided as the emergency escape and rescue opening, it shall have a sill height of not more than 44 inches (1118 mm) above the floor; where the sill height is below grade, it shall be provided with a window well in accordance with Section R310.2.3.

    R310.2.3 Window wells.

    The horizontal area of the window well shall be not less than 9 square feet (0.9 m2), with a horizontal projection and width of not less than 36 inches (914 mm). The area of the window well shall allow the emergency escape and rescue opening to be fully opened.

    Exception: The ladder or steps required by Section R310.2.3.1 shall be permitted to encroach not more than 6 inches (152 mm) into the required dimensions of the window well.

    R310.2.3.1 Ladder and steps.

    Window wells with a vertical depth greater than 44 inches (1118 mm) shall be equipped with a permanently affixed ladder or steps usable with the window in the fully open position. Ladders or steps required by this section shall not be required to comply with Sections R311.7 and R311.8. Ladders or rungs shall have an inside width of not less than 12 inches (305 mm), shall project not less than 3 inches (76 mm) from the wall and shall be spaced not more than 18 inches (457 mm) on center vertically for the full height of the window well.

    R310.2.3.2 Drainage.

    Window wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1 or by an approved alternative method.

    Exception: A drainage system for window wells is not required where the foundation is on well-drained soil or sand-gravel mixture soils in accordance with the United Soil Classification System, Group I Soils, as detailed in Table R405.1.

    R310.2.4 Emergency escape and rescue openings under decks and porches.

    Emergency escape and rescue openings shall be permitted to be installed under decks and porches provided that the location of the deck allows the emergency escape and rescue openings to be fully opened and provides a path not less than 36 inches (914 mm) in height to a yard or court.

    R310.2.5 Replacement windows.

    Replacement windows installed in buildings meeting the scope of this code shall be exempt from the maximum sill height requirements of Sections R310.1 and Sections R310.2.1 and R310.2.2, provided the replacement window meets the following conditions:

    1. 1.The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window is of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.

    2. 2.The replacement window is not part of a change of occupancy.

    R310.3 Emergency escape and rescue doors.

    Where a door is provided as the required emergency escape and rescue opening, it shall be permitted to be a side-hinged door or a slider. Where the opening is below the adjacent ground elevation, it shall be provided with a bulkhead enclosure.

    R310.3.1 Minimum door opening size.

    The minimum net clear height opening for any door that serves as an emergency and escape rescue opening shall be in accordance with Section R310.2.1.

    R310.3.2 Bulkhead enclosures.

    Bulkhead enclosures shall provide direct access from the basement. The bulkhead enclosure shall provide the minimum net clear opening equal to the door in the fully open position.

    R310.3.2.1 Drainage.

    Bulkhead enclosures shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1 or by an approved alternative method.

    Exception: A drainage system for bulkhead enclosures is not required where the foundation is on well-drained soil or sand-gravel mixture soils in accordance with the United Soil Classification System, Group I Soils, as detailed in Table R405.1.

    R310.4 Bars, grilles, covers and screens.

    Bars, grilles, covers, screens or similar devices are permitted to be placed over emergency escape and rescue openings, bulkhead enclosures, or window wells that serve such openings, provided that the minimum net clear opening size complies with Sections R310.1.1 to R310.2.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that required for the normal operation of the escape and rescue opening.

    R310.5 Dwelling additions.

    Where dwelling additions occur that contain sleeping rooms, an emergency escape and rescue opening shall be provided in each new sleeping room. Where dwelling additions occur that have basements, an emergency escape and rescue opening shall be provided in the new basement.

    Exceptions:

    1. 1.An emergency escape and rescue opening is not required in a new basement that contains a sleeping room with an emergency escape and rescue opening.

    2. 2.An emergency escape and rescue opening is not required in a new basement where there is an emergency escape and rescue opening in an existing basement that is accessible from the new basement.

    R310.6 Alterations or repairs of existing basements.

    An emergency escape and rescue opening is not required where existing basements undergo alterations or repairs.

    Exception: New sleeping rooms created in an existing basement shall be provided with emergency escape and rescue openings in accordance with Section R310.1.

    SECTIONR311
    MEANS OF EGRESS

    R311.1 Means of egress.

    Dwellings shall be provided with a means of egress in accordance with this section. The means of egress shall provide a continuous and unobstructed path of vertical and horizontal egress travel from all portions of the dwelling to the required egress door without requiring travel through a garage. The required egress door shall open directly into a public way or to a yard or court that opens to a public way.

    R311.2 Egress door.

    Not less than one egress door shall be provided for each dwelling unit. The egress door shall be side-hinged, and shall provide a clear width of not less than 32 inches (813 mm) where measured between the face of the door and the stop, with the door open 90 degrees (1.57 rad). The clear height of the door opening shall be not less than 78 inches (1981 mm) in height measured from the top of the threshold to the bottom of the stop. Other doors shall not be required to comply with these minimum dimensions. Egress doors shall be readily openable from inside the dwelling without the use of a key or special knowledge or effort.

    R311.3 Floors and landings at exterior doors.

    There shall be a landing or floor on each side of each exterior door. The width of each landing shall be not less than the door served. Every landing shall have a dimension of not less than 36 inches (914 mm) measured in the direction of travel. The slope at exterior landings shall not exceed 1/4 unit vertical in 12 units horizontal (2 percent).

    Exception: Exterior balconies less than 60 square feet (5.6 m2) and only accessible from a door are permitted to have a landing less than 36 inches (914 mm) measured in the direction of travel.

    R311.3.1 Floor elevations at the required egress doors.

    Landings or finished floors at the required egress door shall be not more than 11/2 inches (38 mm) lower than the top of the threshold.

    Exception: The landing or floor on the exterior side shall be not more than 73/4 inches (196 mm) below the top of the threshold provided the door does not swing over the landing or floor.

    Where exterior landings or floors serving the required egress door are not at grade, they shall be provided with access to grade by means of a ramp in accordance with Section R311.8 or a stairway in accordance with Section R311.7.

    R311.3.2 Floor elevations for other exterior doors.

    Doors other than the required egress door shall be provided with landings or floors not more than 73/4 inches (196 mm) below the top of the threshold.

    Exception: A top landing is not required where a stairway of not more than two risers is located on the exterior side of the door, provided that the door does not swing over the stairway.

    R311.3.3 Storm and screen doors.

    Storm and screen doors shall be permitted to swing over exterior stairs and landings.

    R311.4 Vertical egress.

    Egress from habitable levels including habitable attics and basements not provided with an egress door in accordance with Section R311.2 shall be by a ramp in accordance with Section R311.8 or a stairway in accordance with Section R311.7.

    R311.5 Construction.

    R311.5.1 Attachment.

    Exterior landings, decks, balconies, stairs and similar facilities shall be positively anchored to the primary structure to resist both vertical and lateral forces or shall be designed to be self-supporting. Attachment shall not be accomplished by use of toenails or nails subject to withdrawal.

    R311.6 Hallways.

    The width of a hallway shall be not less than 3 feet (914 mm).

    R311.7 Stairways.

    R311.7.1 Width.

    Stairways shall be not less than 36 inches (914 mm) in clear width at all points above the permitted handrail height and below the required headroom height. Handrails shall not project more than 41/2 inches (114 mm) on either side of the stairway and the clear width of the stairway at and below the handrail height, including treads and landings, shall be not less than 311/2 inches (787 mm) where a handrail is installed on one side and 27 inches (698 mm) where handrails are provided on both sides.

    Exception: The width of spiral stairways shall be in accordance with Section R311.7.10.1.

    R311.7.2 Headroom.

    The headroom in stairways shall be not less than 6 feet 8 inches (2032 mm) measured vertically from the sloped line adjoining the tread nosing or from the floor surface of the landing or platform on that portion of the stairway.

    Exceptions:

    1. 1.Where the nosings of treads at the side of a flight extend under the edge of a floor opening through which the stair passes, the floor opening shall be allowed to project horizontally into the required headroom not more than 43/4 inches (121 mm).

    2. 2.The headroom for spiral stairways shall be in accordance with Section R311.7.10.1.

    R311.7.3 Vertical rise.

    A flight of stairs shall not have a vertical rise larger than 147 inches (3734 mm) between floor levels or landings.

    R311.7.4 Walkline.

    The walkline across winder treads shall be concentric to the curved direction of travel through the turn and located 12 inches (305 mm) from the side where the winders are narrower. The 12-inch (305 mm) dimension shall be measured from the widest point of the clear stair width at the walking surface of the winder. If winders are adjacent within the flight, the point of the widest clear stair width of the adjacent winders shall be used.

    R311.7.5 Stair treads and risers.

    Stair treads and risers shall meet the requirements of this section. For the purposes of this section, dimensions and dimensioned surfaces shall be exclusive of carpets, rugs or runners.

    R311.7.5.1 Risers.

    The riser height shall be not more than 73/4 inches (196 mm). The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). Risers shall be vertical or sloped from the underside of the nosing of the tread above at an angle not more than 30 degrees (0.51 rad) from the vertical. Open risers are permitted provided that the openings located more than 30 inches (762 mm), as measured vertically, to the floor or grade below do not permit the passage of a 4-inch-diameter (102 mm) sphere.

    Exceptions:

    1. 1.The opening between adjacent treads is not limited on spiral stairways.

    2. 2.The riser height of spiral stairways shall be in accordance with Section R311.7.10.1.

    R311.7.5.2 Treads.

    The tread depth shall be not less than 10 inches (254 mm). The tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread’s leading edge. The greatest tread depth within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm).

    R311.7.5.2.1 Winder treads.

    Winder treads shall have a tread depth of not less than 10 inches (254 mm) measured between the vertical planes of the foremost projection of adjacent treads at the intersections with the walkline. Winder treads shall have a tread depth of not less than 6 inches (152 mm) at any point within the clear width of the stair. Within any flight of stairs, the largest winder tread depth at the walkline shall not exceed the smallest winder tread by more than 3/8 inch (9.5 mm). Consistently shaped winders at the walkline shall be allowed within the same flight of stairs as rectangular treads and do not have to be within 3/8 inch (9.5 mm) of the rectangular tread depth.

    Exception: The tread depth at spiral stairways shall be in accordance with Section R311.7.10.1.

    R311.7.5.3 Nosings.

    The radius of curvature at the nosing shall be not greater than 9/16 inch (14 mm). A nosing projection not less than 3/4 inch (19 mm) and not more than 11/4 inches (32 mm) shall be provided on stairways with solid risers. The greatest nosing projection shall not exceed the smallest nosing projection by more than 3/8 inch (9.5 mm) between two stories, including the nosing at the level of floors and landings. Beveling of nosings shall not exceed 1/2 inch (12.7 mm).

    Exception: A nosing projection is not required where the tread depth is not less than 11 inches (279 mm).

    R311.7.5.4 Exterior plastic composite stair treads.

    Plastic composite exterior stair treads shall comply with the provisions of this section and Section R507.3.

    R311.7.6 Landings for stairways.

    There shall be a floor or landing at the top and bottom of each stairway. The width perpendicular to the direction of travel shall be not less than the width of the flight served. Landings of shapes other than square or rectangular shall be permitted provided that the depth at the walk line and the total area is not less than that of a quarter circle with a radius equal to the required landing width. Where the stairway has a straight run, the depth in the direction of travel shall be not less than 36 inches (914 mm).

    Exception: A floor or landing is not required at the top of an interior flight of stairs, including stairs in an enclosed garage, provided that a door does not swing over the stairs.

    R311.7.7 Stairway walking surface.

    The walking surface of treads and landings of stairways shall be sloped not steeper than one unit vertical in 48 inches horizontal (2-percent slope).

    R311.7.8 Handrails.

    Handrails shall be provided on not less than one side of each continuous run of treads or flight with four or more risers.

    R311.7.8.1 Height.

    Handrail height, measured vertically from the sloped plane adjoining the tread nosing, or finish surface of ramp slope, shall be not less than 34 inches (864 mm) and not more than 38 inches (965 mm).

    Exceptions:

    1. 1.The use of a volute, turnout or starting easing shall be allowed over the lowest tread.

    2. 2.Where handrail fittings or bendings are used to provide continuous transition between flights, transitions at winder treads, the transition from handrail to guard, or used at the start of a flight, the handrail height at the fittings or bendings shall be permitted to exceed 38 inches (956 mm).

    R311.7.8.2 Continuity.

    Handrails for stairways shall be continuous for the full length of the flight, from a point directly above the top riser of the flight to a point directly above the lowest riser of the flight. Handrail ends shall be returned or shall terminate in newel posts or safety terminals. Handrails adjacent to a wall shall have a space of not less than 11/2 inches (38 mm) between the wall and the handrails.

    Exceptions:

    1. 1.Handrails shall be permitted to be interrupted by a newel post at the turn.

    2. 2.The use of a volute, turnout, starting easing or starting newel shall be allowed over the lowest tread.

    R311.7.8.3 Grip-size.

    Required handrails shall be of one of the following types or provide equivalent graspability.

    1. 1.Type I. Handrails with a circular cross section shall have an outside diameter of not less than 11/4 inches (32 mm) and not greater than 2 inches (51 mm). If the handrail is not circular, it shall have a perimeter dimension of not less than 4 inches (102 mm) and not greater than 61/4 inches (160 mm) with a cross section of dimension of not more than 21/4 inches (57 mm). Edges shall have a radius of not less than 0.01 inch (0.25 mm).

    2. 2.Type II. Handrails with a perimeter greater than 61/4 inches (160 mm) shall have a graspable finger recess area on both sides of the profile. The finger recess shall begin within a distance of 3/4 inch (19 mm) measured vertically from the tallest portion of the profile and achieve a depth of not less than 5/16 inch (8 mm) within 7/8 inch (22 mm) below the widest portion of the profile. This required depth shall continue for not less than 3/8 inch (10 mm) to a level that is not less than 13/4 inches (45 mm) below the tallest portion of the profile. The width of the handrail above the recess shall be not less than 11/4 inches (32 mm) and not more than 23/4 inches (70 mm). Edges shall have a radius of not less than 0.01 inch (0.25 mm).

    R311.7.8.4 Exterior plastic composite handrails.

    Plastic composite exterior handrails shall comply with the requirements of Section R507.3.

    R311.7.9 Illumination.

    Stairways shall be provided with illumination in accordance with Section R303.7.

    R311.7.10 Special stairways.

    Spiral stairways and bulkhead enclosure stairways shall comply with the requirements of Section R311.7 except as specified in Sections R311.7.10.1 and R311.7.10.2.

    R311.7.10.1 Spiral stairways.

    Spiral stairways are permitted, provided that the clear width at and below the handrail is not less than 26 inches (660 mm) and the walkline radius is not greater than 241/2 inches (622 mm). Each tread shall have a depth of not less than 63/4 inches (171 mm) at the walkline. All treads shall be identical, and the rise shall be not more than 91/2 inches (241 mm). Headroom shall be not less than 6 feet 6 inches (1982 mm).

    R311.7.10.2 Bulkhead enclosure stairways.

    Stairways serving bulkhead enclosures, not part of the required building egress, providing access from the outside grade level to the basement shall be exempt from the requirements of Sections R311.3 and R311.7 where the height from the basement finished floor level to grade adjacent to the stairway is not more than 8 feet (2438 mm) and the grade level opening to the stairway is covered by a bulkhead enclosure with hinged doors or other approved means.

    R311.7.11 Alternating tread devices.

    Alternating tread devices shall not be used as an element of a means of egress. Alternating tread devices shall be permitted provided that the required means of egress stairway or ramp serves the same space at each adjoining level or where a means of egress is not required. The clear width at and below the handrails shall be not less than 20 inches (508 mm).

    R311.7.11.1 Treads of alternating tread devices.

    Alternating tread devices shall have a tread depth of not less than 5 inches (127 mm), a projected tread depth of not less than 81/2 inches (216 mm), a tread width of not less than 7 inches (178 mm) and a riser height of not more than 91/2 inches (241 mm). The tread depth shall be measured horizontally between the vertical planes of the foremost projections of adjacent treads. The riser height shall be measured vertically between the leading edges of adjacent treads. The riser height and tread depth provided shall result in an angle of ascent from the horizontal of between 50 and 70 degrees (0.87 and 1.22 rad). The initial tread of the device shall begin at the same elevation as the platform, landing or floor surface.

    R311.7.11.2 Handrails of alternating tread devices.

    Handrails shall be provided on both sides of alternating tread devices and shall comply with Sections R311.7.8.2 to R311.7.8.4. Handrail height shall be uniform, not less than 30 inches (762 mm) and not more than 34 inches (864 mm).

    R311.7.12 Ships ladders.

    Ships ladders shall not be used as an element of a means of egress. Ships ladders shall be permitted provided that a required means of egress stairway or ramp serves the same space at each adjoining level or where a means of egress is not required. The clear width at and below the handrails shall be not less than 20 inches.

    R311.7.12.1 Treads of ships ladders.

    Treads shall have a depth of not less than 5 inches (127 mm). The tread shall be projected such that the total of the tread depth plus the nosing projection is not less than 81/2 inches (216 mm). The riser height shall be not more than 91/2 inches (241 mm).

    R311.7.12.2 Handrails of ships ladders.

    Handrails shall be provided on both sides of ships ladders and shall comply with Sections R311.7.8.2 to R311.7.8.4. Handrail height shall be uniform, not less than 30 inches (762 mm) and not more than 34 inches (864 mm).

    R311.8 Ramps.

    R311.8.1 Maximum slope.

    Ramps serving the egress door required by Section R311.2 shall have a slope of not more than 1 unit vertical in 12 units horizontal (8.3-percent slope). All other ramps shall have a maximum slope of 1 unit vertical in 8 units horizontal (12.5 percent).

    Exception: Where it is technically infeasible to comply because of site constraints, ramps shall have a slope of not more than 1 unit vertical in 8 units horizontal (12.5 percent).

    R311.8.2 Landings required.

    There shall be a floor or landing at the top and bottom of each ramp, where doors open onto ramps, and where ramps change directions. The width of the landing perpendicular to the ramp slope shall be not less than 36 inches (914 mm).

    R311.8.3 Handrails required.

    Handrails shall be provided on not less than one side of ramps exceeding a slope of one unit vertical in 12 units horizontal (8.33-percent slope).

    R311.8.3.1 Height.

    Handrail height, measured above the finished surface of the ramp slope, shall be not less than 34 inches (864 mm) and not more than 38 inches (965 mm).

    R311.8.3.2 Grip size.

    Handrails on ramps shall comply with Section R311.7.8.3.

    R311.8.3.3 Continuity.

    Handrails where required on ramps shall be continuous for the full length of the ramp. Handrail ends shall be returned or shall terminate in newel posts or safety terminals. Handrails adjacent to a wall shall have a space of not less than 11/2 inches (38 mm) between the wall and the handrails.

    SECTIONR312
    GUARDS AND WINDOW FALL PROTECTION  

    R312.1 Guards.

    Guards shall be provided in accordance with Sections R312.1.1 through R312.1.4.

    R312.1.1 Where required.

    Guards shall be located along open-sided walking surfaces, including stairs, ramps and landings, that are located more than 30 inches (762 mm) measured vertically to the floor or grade below at any point within 36 inches (914 mm) horizontally to the edge of the open side. Insect screening shall not be considered as a guard.

    R312.1.2 Height.

    Required guards at open-sided walking surfaces, including stairs, porches, balconies or landings, shall be not less than 36 inches (914 mm) in height as measured vertically above the adjacent walking surface or the line connecting the leading edges of the treads.

    Exceptions:

    1. 1.Guards on the open sides of stairs shall have a height not less than 34 inches (864 mm) measured vertically from a line connecting the leading edges of the treads.

    2. 2.Where the top of the guard serves as a handrail on the open sides of stairs, the top of the guard shall be not less than 34 inches (864 mm) and not more than 38 inches (965 mm) as measured vertically from a line connecting the leading edges of the treads.

    R312.1.3 Opening limitations.

    Required guards shall not have openings from the walking surface to the required guard height that allow passage of a sphere 4 inches (102 mm) in diameter.

    Exceptions:

    1. 1.The triangular openings at the open side of stair, formed by the riser, tread and bottom rail of a guard, shall not allow passage of a sphere 6 inches (153 mm) in diameter.

    2. 2.Guards on the open side of stairs shall not have openings that allow passage of a sphere 43/8 inches (111 mm) in diameter.

    R312.1.4 Exterior plastic composite guards.

    Plastic composite exterior guards shall comply with the requirements of Section R317.4.

    R312.2 Window fall protection.

    Window fall protection shall be provided in accordance with Sections R312.2.1 and R312.2.2.

    R312.2.1 Window sills.

    In dwelling units, where the top of the sill of an operable window opening is located less than 24 inches (610 mm) above the finished floor and greater than 72 inches (1829 mm) above the finished grade or other surface below on the exterior of the building, the operable window shall comply with one of the following:

    1. 1.Operable windows with openings that will not allow a 4-inch-diameter (102 mm) sphere to pass through the opening where the opening is in its largest opened position.

    2. 2.Operable windows that are provided with window fall prevention devices that comply with ASTM F 2090.

    3. 3.Operable windows that are provided with window opening control devices that comply with Section R312.2.2.

    R312.2.2 Window opening control devices.

    Window opening control devices shall comply with ASTM F 2090. The window opening control device, after operation to release the control device allowing the window to fully open, shall not reduce the net clear opening area of the window unit to less than the area required by Section R310.2.1.

    SECTIONR313
    AUTOMATIC FIRE SPRINKLER SYSTEMS

    R313.1 Townhouse automatic fire sprinkler systems.

    An automatic residential fire sprinkler system shall be installed in townhouses.

    Exception: An automatic residential fire sprinkler system shall not be required where additions or alterations are made to existing townhouses that do not have an automatic residential fire sprinkler system installed.

    R313.1.1 Design and installation.

    Automatic residential fire sprinkler systems for townhouses shall be designed and installed in accordance with Section P2904 or NFPA 13D.

    R313.2 One- and two-family dwellings automatic fire systems.

    An automatic residential fire sprinkler system shall be installed in one- and two-family dwellings.

    Exception: An automatic residential fire sprinkler system shall not be required for additions or alterations to existing buildings that are not already provided with an automatic residential sprinkler system.

    R313.2.1 Design and installation.

    Automatic residential fire sprinkler systems shall be designed and installed in accordance with Section P2904 or NFPA 13D.

    SECTIONR314
    SMOKE ALARMS

    R314.1 General.

    Smoke alarms shall comply with NFPA 72 and Section R314.

    R314.1.1 Listings.

    Smoke alarms shall be listed in accordance with UL 217. Combination smoke and carbon monoxide alarms shall be listed in accordance with UL 217 and UL 2034.

    R314.2 Where required.

    Smoke alarms shall be provided in accordance with this section.

    R314.2.1 New construction.

    Smoke alarms shall be provided in dwelling units.

    R314.2.2 Alterations, repairs and additions.

    Where alterations, repairs or additions requiring a permit occur, or where one or more sleeping rooms are added or created in existing dwellings, the individual dwelling unit shall be equipped with smoke alarms located as required for new dwellings.

    Exceptions:

    1. 1.Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding, the addition or replacement of windows or doors, or the addition of a porch or deck, are exempt from the requirements of this section.

    2. 2.Installation, alteration or repairs of plumbing or mechanical systems are exempt from the requirements of this section.

    R314.3 Location.

    Smoke alarms shall be installed in the following locations:

    1. 1.In each sleeping room.

    2. 2.Outside each separate sleeping area in the immediate vicinity of the bedrooms.

    3. 3.On each additional story of the dwelling, including basements and habitable attics and not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.

    4. 4.Smoke alarms shall be installed not less than 3 feet (914 mm) horizontally from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by Section R314.3.

    R314.3.1 Installation near cooking appliances.

    Smoke alarms shall not be installed in the following locations unless this would prevent placement of a smoke alarm in a location required by Section R314.3.

    1. 1.Ionization smoke alarms shall not be installed less than 20 feet (6096 mm) horizontally from a permanently installed cooking appliance.

    2. 2.Ionization smoke alarms with an alarm-silencing switch shall not be installed less than 10 feet (3048 mm) horizontally from a permanently installed cooking appliance.

    3. 3.Photoelectric smoke alarms shall not be installed less than 6 feet (1828 mm) horizontally from a permanently installed cooking appliance.

    R314.4 Interconnection.

    Where more than one smoke alarm is required to be installed within an individual dwelling unit in accordance with Section R314.3, the alarm devices shall be interconnected in such a manner that the actuation of one alarm will activate all of the alarms in the individual dwelling unit. Physical interconnection of smoke alarms shall not be required where listed wireless alarms are installed and all alarms sound upon activation of one alarm.

    Exception: Interconnection of smoke alarms in existing areas shall not be required where alterations or repairs do not result in removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space or basement available that could provide access for interconnection without the removal of interior finishes.

    R314.5 Combination alarms.

    Combination smoke and carbon monoxide alarms shall be permitted to be used in lieu of smoke alarms.

    R314.6 Power source.

    Smoke alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and, where primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection.

    Exceptions:

    1. 1.Smoke alarms shall be permitted to be battery operated where installed in buildings without commercial power.

    2. 2.Smoke alarms installed in accordance with Section R314.2.2 shall be permitted to be battery powered.

    R314.7 Fire alarm systems.

    Fire alarm systems shall be permitted to be used in lieu of smoke alarms and shall comply with Sections R314.7.1 through R314.7.4.

    R314.7.1 General.

    Fire alarm systems shall comply with the provisions of this code and the household fire warning equipment provisions of NFPA 72. Smoke detectors shall be listed in accordance with UL 268.

    R314.7.2 Location.

    Smoke detectors shall be installed in the locations specified in Section R314.3.

    R314.7.3 Permanent fixture.

    Where a household fire alarm system is installed, it shall become a permanent fixture of the occupancy, owned by the homeowner.

    R314.7.4 Combination detectors.

    Combination smoke and carbon monoxide detectors shall be permitted to be installed in fire alarm systems in lieu of smoke detectors, provided that they are listed in accordance with UL 268 and UL 2075.

    SECTIONR315
    CARBON MONOXIDE ALARMS

    R315.1 General.

    Carbon monoxide alarms shall comply with Section R315.

    R315.1.1 Listings.

    Carbon monoxide alarms shall be listed in accordance with UL 2034. Combination carbon monoxide and smoke alarms shall be listed in accordance with UL 2034 and UL 217.

    R315.2 Where required.

    Carbon monoxide alarms shall be provided in accordance with Sections R315.2.1 and R315.2.2.

    R315.2.1 New construction.

    For new construction, carbon monoxide alarms shall be provided in dwelling units where either or both of the following conditions exist.

    1. 1.The dwelling unit contains a fuel-fired appliance.

    2. 2.The dwelling unit has an attached garage with an opening that communicates with the dwelling unit.

    R315.2.2 Alterations, repairs and additions.

    Where alterations, repairs or additions requiring a permit occur, or where one or more sleeping rooms are added or created in existing dwellings, the individual dwelling unit shall be equipped with carbon monoxide alarms located as required for new dwellings.

    Exceptions:

    1. 1.Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck, is exempt from the requirements of this section.

    2. 2.Installation, alteration or repairs of plumbing or mechanical systems are exempt from the requirements of this section.

    R315.3 Location.

    Carbon monoxide alarms in dwelling units shall be installed outside of each separate sleeping area in the immediate vicinity of the bedrooms. Where a fuel-burning appliance is located within a bedroom or its attached bathroom, a carbon monoxide alarm shall be installed within the bedroom.

    R315.4 Combination alarms.

    Combination carbon monoxide and smoke alarms shall be permitted to be used in lieu of carbon monoxide alarms.

    R315.5 Power source.

    Carbon monoxide alarms shall receive their primary power from the building wiring where such wiring is served from a commercial source and, where primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection.

    Exceptions:

    1. 1.Carbon monoxide alarms shall be permitted to be battery operated where installed in buildings without commercial power.

    2. 2.Carbon monoxide alarms installed in accordance with Section R315.2.2 shall be permitted to be battery powered.

    R315.6 Carbon monoxide detection systems.

    Carbon monoxide detection systems shall be permitted to be used in lieu of carbon monoxide alarms and shall comply with Sections R315.6.1 through R315.6.4.

    R315.6.1 General.

    Household carbon monoxide detection systems shall comply with NFPA 720. Carbon monoxide detectors shall be listed in accordance with UL 2075.

    R315.6.2 Location.

    Carbon monoxide detectors shall be installed in the locations specified in Section R315.3. These locations supersede the locations specified in NFPA 720.

    R315.6.3 Permanent fixture.

    Where a household carbon monoxide detection system is installed, it shall become a permanent fixture of the occupancy and owned by the homeowner.

    R315.6.4 Combination detectors.

    Combination carbon monoxide and smoke detectors shall be permitted to be installed in carbon monoxide detection systems in lieu of carbon monoxide detectors, provided that they are listed in accordance with UL 2075 and UL 268.

    SECTIONR316
    FOAM PLASTIC  

    R316.1 General.

    The provisions of this section shall govern the materials, design, application, construction and installation of foam plastic materials.

    R316.2 Labeling and identification.

    Packages and containers of foam plastic insulation and foam plastic insulation components delivered to the job site shall bear the label of an approved agency showing the manufacturer’s name, the product listing, product identification and information sufficient to determine that the end use will comply with the requirements.

    R316.3 Surface burning characteristics.

    Unless otherwise allowed in Section R316.5, foam plastic or foam plastic cores used as a component in manufactured assemblies used in building construction shall have a flame spread index of not more than 75 and shall have a smoke-developed index of not more than 450 when tested in the maximum thickness and density intended for use in accordance with ASTM E 84 or UL 723. Loose-fill-type foam plastic insulation shall be tested as board stock for the flame spread index and smoke-developed index.

    Exception: Foam plastic insulation more than 4 inches (102 mm) thick shall have a flame spread index of not more than 75 and a smoke-developed index of not more than 450 where tested at a thickness of not more than 4 inches (102 mm), provided that the end use is approved in accordance with Section R316.6 using the thickness and density intended for use.

    R316.4 Thermal barrier.

    Unless otherwise allowed in Section R316.5, foam plastic shall be separated from the interior of a building by an approved thermal barrier of not less than 1/2-inch (12.7 mm) gypsum wallboard, 23/32-inch (18.2 mm) wood structural panel or a material that is tested in accordance with and meets the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA 275.

    R316.5 Specific requirements.

    The following requirements shall apply to these uses of foam plastic unless specifically approved in accordance with Section R316.6 or by other sections of the code or the requirements of Sections R316.2 through R316.4 have been met.

    R316.5.1 Masonry or concrete construction.

    The thermal barrier specified in Section R316.4 is not required in a masonry or concrete wall, floor or roof when the foam plastic insulation is separated from the interior of the building by not less than a 1-inch (25 mm) thickness of masonry or concrete.

    R316.5.2 Roofing.

    The thermal barrier specified in Section R316.4 is not required where the foam plastic in a roof assembly or under a roof covering is installed in accordance with the code and the manufacturer’s instructions and is separated from the interior of the building by tongue-and-groove wood planks or wood structural panel sheathing, in accordance with Section R803, that is not less than 15/32 inch (11.9 mm) thick bonded with exterior glue, identified as Exposure 1 and with edges supported by blocking or tongue-and-groove joints or an equivalent material. The smoke-developed index for roof applications shall not be limited.

    R316.5.3 Attics.

    The thermal barrier specified in Section R316.4 is not required where all of the following apply:

    1. 1.Attic access is required by Section R807.1.

    2. 2.The space is entered only for purposes of repairs or maintenance.

    3. 3.The foam plastic insulation has been tested in accordance with Section R316.6 or the foam plastic insulation is protected against ignition using one of the following ignition barrier materials:

      1. 3.1.11/2-inch-thick (38 mm) mineral fiber insulation.

      2. 3.2.1/4-inch-thick (6.4 mm) wood structural panels.

      3. 3.3.3/8-inch (9.5 mm) particleboard.

      4. 3.4.1/4-inch (6.4 mm) hardboard.

      5. 3.5.3/8-inch (9.5 mm) gypsum board.

      6. 3.6.Corrosion-resistant steel having a base metal thickness of 0.016 inch (0.406 mm).

      7. 3.7.11/2-inch-thick (38 mm) cellulose insulation; or

      8. 3.8.1/4-inch (6.4 mm) fiber-cement panel, soffit or backer board.

    The ignition barrier is not required where the foam plastic insulation has been tested in accordance with Section R316.6.

    R316.5.4 Crawl spaces.

    The thermal barrier specified in Section R316.4 is not required where all of the following apply:

    1. 1.Crawl space access is required by Section R408.4.

    2. 2.Entry is made only for purposes of repairs or maintenance.

    3. 3.The foam plastic insulation has been tested in accordance with Section R316.6 or the foam plastic insulation is protected against ignition using one of the following ignition barrier materials:

      1. 3.1.11/2-inch-thick (38 mm) mineral fiber insulation;

      2. 3.2.1/4-inch-thick (6.4 mm) wood structural panels;

      3. 3.3.3/8-inch (9.5 mm) particleboard;

      4. 3.4.1/4-inch (6.4 mm) hardboard;

      5. 3.5.3/8-inch (9.5 mm) gypsum board; or

      6. 3.6.Corrosion-resistant steel having a base metal thickness of 0.016 inch (0.406 mm).

    R316.5.5 Foam-filled exterior doors.

    Foam-filled exterior doors are exempt from the requirements of Sections R316.3 and R316.4.

    R316.5.6 Foam-filled garage doors.

    Foam-filled garage doors in attached or detached garages are exempt from the requirements of Sections R316.3 and R316.4.

    R316.5.7 Foam backer board.

    The thermal barrier specified in Section R316.4 is not required where siding backer board foam plastic insulation has a thickness of not more than 0.5 inch (12.7 mm) and a potential heat of not more than 2000 Btu per square foot (22 720 kJ/m2) when tested in accordance with NFPA 259 provided that:

    1. 1.The foam plastic insulation is separated from the interior of the building by not less than 2 inches (51 mm) of mineral fiber insulation;

    2. 2.The foam plastic insulation is installed over existing exterior wall finish in conjunction with re-siding; or

    3. 3.The foam plastic insulation has been tested in accordance with Section R316.6.

    R316.5.8 Re-siding.

    The thermal barrier specified in Section R316.4 is not required where the foam plastic insulation is installed over existing exterior wall finish in conjunction with re-siding provided that the foam plastic has a thickness of not more than 0.5 inch (12.7 mm) and a potential heat of not more than 2000 Btu per square foot (22 720 kJ/m2) when tested in accordance with NFPA 259.

    R316.5.9 Interior trim.

    The thermal barrier specified in Section R316.4 is not required for exposed foam plastic interior trim, provided that all of the following are met:

    1. 1.The density is not less than 20 pounds per cubic foot (320 kg/m3).

    2. 2.The thickness of the trim is not more than 0.5 inch (12.7 mm) and the width is not more than 8 inches (204 mm).

    3. 3.The interior trim shall not constitute more than 10 percent of the aggregate wall and ceiling area of any room or space.

    4. 4.The flame spread index does not exceed 75 when tested per ASTM E 84 or UL 723. The smoke-developed index is not limited.

    R316.5.10 Interior finish.

    Foam plastics shall be permitted as interior finish where approved in accordance with Section R316.6. Foam plastics that are used as an interior finish shall meet the flame spread index and smoke-developed index requirements of Sections R302.9.1 and R302.9.2.

    R316.5.11 Sill plates and headers.

    Foam plastic shall be permitted to be spray applied to sill plates and headers or installed in the perimeter joist space without the thermal barrier specified in Section R316.4 subject to all of the following:

    1. 1.The thickness of the foam plastic shall be not more than 31/4 inches (83 mm).

    2. 2.The density of the foam plastic shall be in the range of 0.5 to 2.0 pounds per cubic foot (8 to 32 kg/m3).

    3. 3.The foam plastic shall have a flame spread index of 25 or less and an accompanying smoke-developed index of 450 or less when tested in accordance with ASTM E 84 or UL 723.

    R316.5.12 Sheathing.

    Foam plastic insulation used as sheathing shall comply with Section R316.3 and Section R316.4. Where the foam plastic sheathing is exposed to the attic space at a gable or kneewall, the provisions of Section R316.5.3 shall apply. Where foam plastic insulation is used as exterior wall sheathing on framed wall assemblies, it shall comply with Section R316.8.

    R316.5.13 Floors.

    The thermal barrier specified in Section R316.4 is not required to be installed on the walking surface of a structural floor system that contains foam plastic insulation when the foam plastic is covered by not more than a nominal 1/2-inch-thick (12.7 mm) wood structural panel or equivalent. The thermal barrier specified in Section R316.4 is required on the underside of the structural floor system that contains foam plastic insulation when the underside of the structural floor system is exposed to the interior of the building.

    R316.6 Specific approval.

    Foam plastic not meeting the requirements of Sections R316.3 through R316.5 shall be specifically approved on the basis of one of the following approved tests: NFPA 286 with the acceptance criteria of Section R302.9.4, FM 4880, UL 1040 or UL 1715, or fire tests related to actual end-use configurations. Approval shall be based on the actual end-use configuration and shall be performed on the finished foam plastic assembly in the maximum thickness intended for use. Assemblies tested shall include seams, joints and other typical details used in the installation of the assembly and shall be tested in the manner intended for use.

    R316.7 Termite damage.

    The use of foam plastics in areas of “very heavy” termite infestation probability shall be in accordance with Section R318.4.

    R316.8 Wind resistance.

    Foam plastic insulation complying with ASTM C 578 and ASTM C 1289 and used as exterior wall sheathing on framed wall assemblies shall comply with SBCA FS 100 for wind pressure resistance unless installed directly over a sheathing material that is separately capable of resisting the wind load or otherwise exempted from the scope of SBCA FS 100.

    SECTIONR317
    PROTECTION OF WOOD AND WOOD-BASED
    PRODUCTS AGAINST DECAY
     

    R317.1 Location required.

    Protection of wood and wood-based products from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative-treated in accordance with AWPA U1 for the species, product, preservative and end use. Preservatives shall be listed in Section 4 of AWPA U1.

    1. 1.Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation.

    2. 2.Wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.

    3. 3.Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.

    4. 4.The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 1/2 inch (12.7 mm) on tops, sides and ends.

    5. 5.Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground or less than 2 inches (51 mm) measured vertically from concrete steps, porch slabs, patio slabs and similar horizontal surfaces exposed to the weather.

    6. 6.Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.

    7. 7.Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.

    R317.1.1 Field treatment.

    Field-cut ends, notches and drilled holes of preservative-treated wood shall be treated in the field in accordance with AWPA M4.

    R317.1.2 Ground contact.

    All wood in contact with the ground, embedded in concrete in direct contact with the ground or embedded in concrete exposed to the weather that supports permanent structures intended for human occupancy shall be approved pressure-preservative-treated wood suitable for ground contact use, except that untreated wood used entirely below groundwater level or continuously submerged in fresh water shall not be required to be pressure-preservative treated.

    R317.1.3 Geographical areas.

    In geographical areas where experience has demonstrated a specific need, approved naturally durable or pressure-preservative-treated wood shall be used for those portions of wood members that form the structural supports of buildings, balconies, porches or similar permanent building appurtenances when those members are exposed to the weather without adequate protection from a roof, eave, overhang or other covering that would prevent moisture or water accumulation on the surface or at joints between members. Depending on local experience, such members may include:

    1. 1.Horizontal members such as girders, joists and decking.

    2. 2.Vertical members such as posts, poles and columns.

    3. 3.Both horizontal and vertical members.

    R317.1.4 Wood columns.

    Wood columns shall be approved wood of natural decay resistance or approved pressure-preservative-treated wood.

    Exceptions:

    1. 1.Columns exposed to the weather or in basements where supported by concrete piers or metal pedestals projecting 1 inch (25 mm) above a concrete floor or 6 inches (152 mm) above exposed earth and the earth is covered by an approved impervious moisture barrier.

    2. 2.Columns in enclosed crawl spaces or unexcavated areas located within the periphery of the building when supported by a concrete pier or metal pedestal at a height more than 8 inches (203 mm) from exposed earth and the earth is covered by an impervious moisture barrier.

    3. 3.Deck posts supported by concrete piers or metal pedestals projecting not less than 1 inch (25 mm) above a concrete floor or 6 inches (152 mm) above exposed earth.

    R317.1.5 Exposed glued-laminated timbers.

    The portions of glued-laminated timbers that form the structural supports of a building or other structure and are exposed to weather and not properly protected by a roof, eave or similar covering shall be pressure treated with preservative, or be manufactured from naturally durable or preservative-treated wood.

    R317.2 Quality mark.

    Lumber and plywood required to be pressure-preservative treated in accordance with Section R318.1 shall bear the quality mark of an approved inspection agency that maintains continuing supervision, testing and inspection over the quality of the product and that has been approved by an accreditation body that complies with the requirements of the American Lumber Standard Committee treated wood program.

    R317.2.1 Required information.

    The required quality mark on each piece of pressure-preservative-treated lumber or plywood shall contain the following information:

    1. 1.Identification of the treating plant.

    2. 2.Type of preservative.

    3. 3.The minimum preservative retention.

    4. 4.End use for which the product was treated.

    5. 5.Standard to which the product was treated.

    6. 6.Identity of the approved inspection agency.

    7. 7.The designation “Dry,” if applicable.

    Exception: Quality marks on lumber less than 1 inch (25 mm) nominal thickness, or lumber less than nominal 1 inch by 5 inches (25 mm by 127 mm) or 2 inches by 4 inches (51 mm by 102 mm) or lumber 36 inches (914 mm) or less in length shall be applied by stamping the faces of exterior pieces or by end labeling not less than 25 percent of the pieces of a bundled unit.

    R317.3 Fasteners and connectors in contact with preservative-treated and fire-retardant-treated wood.

    Fasteners, including nuts and washers, and connectors in contact with preservative-treated wood and fire-retardant-treated wood shall be in accordance with this section. The coating weights for zinc-coated fasteners shall be in accordance with ASTM A 153. Stainless steel driven fasteners shall be in accordance with the material requirements of ASTM F 1667.

    R317.3.1 Fasteners for preservative-treated wood.

    Fasteners, including nuts and washers, for preservative-treated wood shall be of hot-dipped, zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Coating types and weights for connectors in contact with preservative-treated wood shall be in accordance with the connector manufacturer’s recommendations. In the absence of manufacturer’s recommendations, a minimum of ASTM A 653 type G185 zinc-coated galvanized steel, or equivalent, shall be used.

    Exceptions:

    1. 1.1/2-inch-diameter (12.7 mm) or greater steel bolts.

    2. 2.Fasteners other than nails and timber rivets shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum.

    3. 3.Plain carbon steel fasteners in SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment shall be permitted.

    R317.3.2 Fastenings for wood foundations.

    Fastenings, including nuts and washers, for wood foundations shall be as required in AF&PA PWF.

    R317.3.3 Fasteners for fire-retardant-treated wood used in exterior applications or wet or damp locations.

    Fasteners, including nuts and washers, for fire-retardant-treated wood used in exterior applications or wet or damp locations shall be of hot-dipped, zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Fasteners other than nails and timber rivets shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum.

    R317.3.4 Fasteners for fire-retardant-treated wood used in interior applications.

    Fasteners, including nuts and washers, for fire-retardant-treated wood used in interior locations shall be in accordance with the manufacturer’s recommendations. In the absence of the manufacturer’s recommendations, Section R317.3.3 shall apply.

    R317.4 Plastic composites.

    Plastic composite exterior deck boards, stair treads, guards and handrails containing wood, cellulosic or other biodegradable materials shall comply with the requirements of Section R507.3.

    SECTIONR318
    PROTECTION AGAINST SUBTERRANEAN TERMITES

    R318.1 Subterranean termite control methods.

    In areas subject to damage from termites as indicated by Table R301.2(1), methods of protection shall be one, or a combination, of the following methods:

    1. 1.Chemical termiticide treatment in accordance with Section R318.2.

    2. 2.Termite baiting system installed and maintained in accordance with the label.

    3. 3.Pressure-preservative-treated wood in accordance with the provisions of Section R317.1.

    4. 4.Naturally durable termite-resistant wood.

    5. 5.Physical barriers in accordance with Section R318.3 and used in locations as specified in Section R317.1.

    6. 6.Cold-formed steel framing in accordance with Sections R505.2.1 and R603.2.1.

    R318.1.1 Quality mark.

    Lumber and plywood required to be pressure-preservative treated in accordance with Section R318.1 shall bear the quality mark of an approved inspection agency that maintains continuing supervision, testing and inspection over the quality of the product and that has been approved by an accreditation body that complies with the requirements of the American Lumber Standard Committee treated wood program.

    R318.1.2 Field treatment.

    Field-cut ends, notches and drilled holes of pressure-preservative-treated wood shall be retreated in the field in accordance with AWPA M4.

    R318.2 Chemical termiticide treatment.

    Chemical termiticide treatment shall include soil treatment or field-applied wood treatment. The concentration, rate of application and method of treatment of the chemical termiticide shall be in strict accordance with the termiticide label.

    R318.3 Barriers.

    Approved physical barriers, such as metal or plastic sheeting or collars specifically designed for termite prevention, shall be installed in a manner to prevent termites from entering the structure. Shields placed on top of an exterior foundation wall are permitted to be used only if in combination with another method of protection.

    R318.4 Foam plastic protection.

    In areas where the probability of termite infestation is “very heavy” as indicated in Figure R301.2(6), extruded and expanded polystyrene, polyisocyanurate and other foam plastics shall not be installed on the exterior face or under interior or exterior foundation walls or slab foundations located below grade. The clearance between foam plastics installed above grade and exposed earth shall be not less than 6 inches (152 mm).

    Exceptions:

    1. 1.Buildings where the structural members of walls, floors, ceilings and roofs are entirely of noncombustible materials or pressure-preservative-treated wood.

    2. 2.Where in addition to the requirements of Section R318.1, an approved method of protecting the foam plastic and structure from subterranean termite damage is used.

    3. 3.On the interior side of basement walls.

    SECTIONR319
    SITE ADDRESS

    R319.1 Address identification.

    Buildings shall be provided with approved address identification. The address identification shall be legible and placed in a position that is visible from the street or road fronting the property. Address identification characters shall contrast with their background. Address numbers shall be Arabic numbers or alphabetical letters. Numbers shall not be spelled out. Each character shall be not less than 4 inches (102 mm) in height with a stroke width of not less than 0.5 inch (12.7 mm). Where required by the fire code official, address identification shall be provided in additional approved locations to facilitate emergency response. Where access is by means of a private road and the building address cannot be viewed from the public way, a monument, pole or other sign or means shall be used to identify the structure. Address identification shall be maintained.

    SECTIONR320
    ACCESSIBILITY

    R320.1 Scope.

    Where there are four or more dwelling units or sleeping units in a single structure, the provisions of Chapter 11 of the International Building Code for Group R-3 shall apply.

    R320.1.1 Guestrooms.

    A dwelling with guestrooms shall comply with the provisions of Chapter 11 of the International Building Code for Group R-3. For the purpose of applying the requirements of Chapter 11 of the International Building Code, guestrooms shall be considered to be sleeping units.

    Exception: Owner-occupied lodging houses with five or fewer guestrooms constructed in accordance with the International Residential Code are not required to be accessible.

    SECTIONR321
    ELEVATORS AND PLATFORM LIFTS

    R321.1 Elevators.

    Where provided, passenger elevators, limited-use and limited-application elevators or private residence elevators shall comply with ASME A17.1/CSA B44.

    R321.2 Platform lifts.

    Where provided, platform lifts shall comply with ASME A18.1.

    R321.3 Accessibility.

    Elevators or platform lifts that are part of an accessible route required by Chapter 11 of the International Building Code, shall comply with ICC A117.1.

    SECTIONR322
    FLOOD-RESISTANT CONSTRUCTION  

    R322.1 General.

    Buildings and structures constructed in whole or in part in flood hazard areas, including A or V Zones and Coastal A Zones, as established in Table R301.2(1), and substantial improvement and restoration of substantial damage of buildings and structures in flood hazard areas, shall be designed and constructed in accordance with the provisions contained in this section. Buildings and structures that are located in more than one flood hazard area shall comply with the provisions associated with the most restrictive flood hazard area. Buildings and structures located in whole or in part in identified floodways shall be designed and constructed in accordance with ASCE 24.

    R322.1.1 Alternative provisions.

    As an alternative to the requirements in Section R322, ASCE 24 is permitted subject to the limitations of this code and the limitations therein.

    R322.1.2 Structural systems.

    Structural systems of buildings and structures shall be designed, connected and anchored to resist flotation, collapse or permanent lateral movement due to structural loads and stresses from flooding equal to the design flood elevation.

    R322.1.3 Flood-resistant construction.

    Buildings and structures erected in areas prone to flooding shall be constructed by methods and practices that minimize flood damage.

    R322.1.4 Establishing the design flood elevation.

    The design flood elevation shall be used to define flood hazard areas. At a minimum, the design flood elevation shall be the higher of the following:

    1. 1.The base flood elevation at the depth of peak elevation of flooding, including wave height, that has a 1 percent (100-year flood) or greater chance of being equaled or exceeded in any given year; or

    2. 2.The elevation of the design flood associated with the area designated on a flood hazard map adopted by the community, or otherwise legally designated.

    R322.1.4.1 Determination of design flood elevations.

    If design flood elevations are not specified, the building official is authorized to require the applicant to comply with either of the following:

    1. 1.Obtain and reasonably use data available from a federal, state or other source; or

    2. 2.Determine the design flood elevation in accordance with accepted hydrologic and hydraulic engineering practices used to define special flood hazard areas. Determinations shall be undertaken by a registered design professional who shall document that the technical methods used reflect currently accepted engineering practice. Studies, analyses and computations shall be submitted in sufficient detail to allow thorough review and approval.

    R322.1.4.2 Determination of impacts.

    In riverine flood hazard areas where design flood elevations are specified but floodways have not been designated, the applicant shall demonstrate that the effect of the proposed buildings and structures on design flood elevations, including fill, when combined with other existing and anticipated flood hazard area encroachments, will not increase the design flood elevation more than 1 foot (305 mm) at any point within the jurisdiction.

    R322.1.5 Lowest floor.

    The lowest floor shall be the lowest floor of the lowest enclosed area, including basement, and excluding any unfinished flood-resistant enclosure that is useable solely for vehicle parking, building access or limited storage provided that such enclosure is not built so as to render the building or structure in violation of this section.

    R322.1.6 Protection of mechanical, plumbing and electrical systems.

    Electrical systems, equipment and components; heating, ventilating, air conditioning; plumbing appliances and plumbing fixtures; duct systems; and other service equipment shall be located at or above the elevation required in Section R322.2 or R322.3. If replaced as part of a substantial improvement, electrical systems, equipment and components; heating, ventilating, air conditioning and plumbing appliances and plumbing fixtures; duct systems; and other service equipment shall meet the requirements of this section. Systems, fixtures, and equipment and components shall not be mounted on or penetrate through walls intended to break away under flood loads.

    Exception: Locating electrical systems, equipment and components; heating, ventilating, air conditioning; plumbing appliances and plumbing fixtures; duct systems; and other service equipment is permitted below the elevation required in Section R322.2 or R322.3 provided that they are designed and installed to prevent water from entering or accumulating within the components and to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding to the design flood elevation in accordance with ASCE 24. Electrical wiring systems are permitted to be located below the required elevation provided that they conform to the provisions of the electrical part of this code for wet locations.

    R322.1.7 Protection of water supply and sanitary sewage systems.

    New and replacement water supply systems shall be designed to minimize or eliminate infiltration of flood waters into the systems in accordance with the plumbing provisions of this code. New and replacement sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into systems and discharges from systems into floodwaters in accordance with the plumbing provisions of this code and Chapter 3 of the International Private Sewage Disposal Code.

    R322.1.8 Flood-resistant materials.

    Building materials and installation methods used for flooring and interior and exterior walls and wall coverings below the elevation required in Section R322.2 or R322.3 shall be flood damage-resistant materials that conform to the provisions of FEMA TB-2.

    R322.1.9 Manufactured homes.

    The bottom of the frame of new and replacement manufactured homes on foundations that conform to the requirements of Section R322.2 or R322.3, as applicable, shall be elevated to or above the elevations specified in Section R322.2 (flood hazard areas including A Zones) or R322.3 in coastal high-hazard areas (V Zones and Coastal A Zones). The anchor and tie-down requirements of the applicable state or federal requirements shall apply. The foundation and anchorage of manufactured homes to be located in identified floodways shall be designed and constructed in accordance with ASCE 24.

    R322.1.10 As-built elevation documentation.

    A registered design professional shall prepare and seal documentation of the elevations specified in Section R322.2 or R322.3.

    R322.2 Flood hazard areas (including A Zones).

    Areas that have been determined to be prone to flooding and that are not subject to high-velocity wave action shall be designated as flood hazard areas. Flood hazard areas that have been delineated as subject to wave heights between 11/2 feet (457 mm) and 3 feet (914 mm) or otherwise designated by the jurisdiction shall be designated as Coastal A Zones and are subject to the requirements of Section R322.3. Buildings and structures constructed in whole or in part in flood hazard areas shall be designed and constructed in accordance with Sections R322.2.1 through R322.2.3.

    R322.2.1 Elevation requirements.

    1. 1.Buildings and structures in flood hazard areas, including flood hazard areas designated as Coastal A Zones, shall have the lowest floors elevated to or above the base flood elevation plus 1 foot (305 mm), or the design flood elevation, whichever is higher.

    2. 2.In areas of shallow flooding (AO Zones), buildings and structures shall have the lowest floor (including basement) elevated to a height above the highest adjacent grade of not less than the depth number specified in feet (mm) on the FIRM plus 1 foot (305 mm), or not less than 3 feet (915 mm) if a depth number is not specified.

    3. 3.Basement floors that are below grade on all sides shall be elevated to or above base flood elevation plus 1 foot (305 mm), or the design flood elevation, whichever is higher.

    Exception: Enclosed areas below the design flood elevation, including basements with floors that are not below grade on all sides, shall meet the requirements of Section R322.2.2.

    R322.2.2 Enclosed area below design flood elevation.

    Enclosed areas, including crawl spaces, that are below the design flood elevation shall:

    1. 1.Be used solely for parking of vehicles, building access or storage.

    2. 2.Be provided with flood openings that meet the following criteria and are installed in accordance with Section R322.2.2.1:

      1. 2.1.The total net area of openings shall be not less than 1 square inch (645 mm2) for each square foot (0.093 m2) of enclosed area where the enclosed area is measured on the exterior of the enclosure walls, or the openings shall be designed as engineered openings and the construction documents shall include a statement by a registered design professional that the design of the openings will provide for equalization of hydrostatic flood forces on exterior walls by allowing for the automatic entry and exit of floodwaters as specified in Section 2.6.2.2 of ASCE 24.

      2. 2.2.Openings shall be not less than 3 inches (76 mm) in any direction in the plane of the wall.

      3. 2.3.The presence of louvers, blades, screens and faceplates or other covers and devices shall allow the automatic flow of floodwater into and out of the enclosed areas and shall be accounted for in the determination of the net open area.

    R322.2.2.1 Installation of openings.

    The walls of enclosed areas shall have openings installed such that:

    1. 1.There shall be not less than two openings on different sides of each enclosed area; if a building has more than one enclosed area below the design flood elevation, each area shall have openings.

    2. 2.The bottom of each opening shall be not more than 1 foot (305 mm) above the higher of the final interior grade or floor and the finished exterior grade immediately under each opening.

    3. 3.Openings shall be permitted to be installed in doors and windows; doors and windows without installed openings do not meet the requirements of this section.

    R322.2.3 Foundation design and construction.

    Foundation walls for buildings and structures erected in flood hazard areas shall meet the requirements of Chapter 4.

    Exception: Unless designed in accordance with Section R404:

    1. 1.The unsupported height of 6-inch (152 mm) plain masonry walls shall be not more than 3 feet (914 mm).

    2. 2.The unsupported height of 8-inch (203 mm) plain masonry walls shall be not more than 4 feet (1219 mm).

    3. 3.The unsupported height of 8-inch (203 mm) reinforced masonry walls shall be not more than 8 feet (2438 mm).

    For the purpose of this exception, unsupported height is the distance from the finished grade of the under-floor space to the top of the wall.

    R322.2.4 Tanks.

    Underground tanks shall be anchored to prevent flotation, collapse and lateral movement under conditions of the base flood. Above-ground tanks shall be installed at or above the elevation required in Section R322.2.1 or shall be anchored to prevent flotation, collapse and lateral movement under conditions of the base flood.

    R322.3 Coastal high-hazard areas (including V Zones and Coastal A Zones, where designated).

    Areas that have been determined to be subject to wave heights in excess of 3 feet (914 mm) or subject to high-velocity wave action or wave-induced erosion shall be designated as coastal high-hazard areas. Flood hazard areas that have been designated as subject to wave heights between 11/2 feet (457 mm) and 3 feet (914 mm) or otherwise designated by the jurisdiction shall be designated as Coastal A Zones. Buildings and structures constructed in whole or in part in coastal high-hazard areas and coastal A Zones, where designated, shall be designed and constructed in accordance with Sections R322.3.1 through R322.3.7.

    R322.3.1 Location and site preparation.

    1. 1.New buildings and buildings that are determined to be substantially improved pursuant to Section R105.3.1.1 shall be located landward of the reach of mean high tide.

    2. 2.For any alteration of sand dunes and mangrove stands, the building official shall require submission of an engineering analysis that demonstrates that the proposed alteration will not increase the potential for flood damage.

    R322.3.2 Elevation requirements.

    1. 1.Buildings and structures erected within coastal high-hazard areas and Coastal A Zones, shall be elevated so that the bottom of the lowest horizontal structural members supporting the lowest floor, with the exception of piling, pile caps, columns, grade beams and bracing, is elevated to or above the base flood elevation plus 1 foot (305 mm) or the design flood elevation, whichever is higher.

    2. 2.Basement floors that are below grade on all sides are prohibited.

    3. 3.The use of fill for structural support is prohibited.

    4. 4.Minor grading, and the placement of minor quantities of fill, shall be permitted for landscaping and for drainage purposes under and around buildings and for support of parking slabs, pool decks, patios and walkways.

    5. 5.Walls and partitions enclosing areas below the design flood elevation shall meet the requirements of Sections R322.3.4 and R322.3.5.

    R322.3.3 Foundations.

    Buildings and structures erected in coastal high-hazard areas and Coastal A Zones shall be supported on pilings or columns and shall be adequately anchored to such pilings or columns. The space below the elevated building shall be either free of obstruction or, if enclosed with walls, the walls shall meet the requirements of Section R322.3.4. Pilings shall have adequate soil penetrations to resist the combined wave and wind loads (lateral and uplift). Water-loading values used shall be those associated with the design flood. Wind-loading values shall be those required by this code. Pile embedment shall include consideration of decreased resistance capacity caused by scour of soil strata surrounding the piling. Pile systems design and installation shall be certified in accordance with Section R322.3.6. Spread footing, mat, raft or other foundations that support columns shall not be permitted where soil investigations that are required in accordance with Section R401.4 indicate that soil material under the spread footing, mat, raft or other foundation is subject to scour or erosion from wave-velocity flow conditions. If permitted, spread footing, mat, raft or other foundations that support columns shall be designed in accordance with ASCE 24. Slabs, pools, pool decks and walkways shall be located and constructed to be structurally independent of buildings and structures and their foundations to prevent transfer of flood loads to the buildings and structures during conditions of flooding, scour or erosion from wave-velocity flow conditions, unless the buildings and structures and their foundations are designed to resist the additional flood load.

    Exception: In Coastal A Zones, stem wall foundations supporting a floor system above and backfilled with soil or gravel to the underside of the floor system shall be permitted provided the foundations are designed to account for wave action, debris impact, erosion and local scour. Where soils are susceptible to erosion and local scour, stem wall foundations shall have deep footings to account for the loss of soil.

    R322.3.4 Walls below design flood elevation.

    Walls and partitions are permitted below the elevated floor, provided that such walls and partitions are not part of the structural support of the building or structure and:

    1. 1.Electrical, mechanical and plumbing system components are not to be mounted on or penetrate through walls that are designed to break away under flood loads; and

    2. 2.Are constructed with insect screening or open lattice; or

    3. 3.Are designed to break away or collapse without causing collapse, displacement or other structural damage to the elevated portion of the building or supporting foundation system. Such walls, framing and connections shall have a resistance of not less than 10 (479 Pa) and not more than 20 pounds per square foot (958 Pa) as determined using allowable stress design; or

    4. 4.Where wind loading values of this code exceed 20 pounds per square foot (958 Pa), as determined using allowable stress design, the construction documents shall include documentation prepared and sealed by a registered design professional that:

      1. 4.1.The walls and partitions below the design flood elevation have been designed to collapse from a water load less than that which would occur during the base flood.

      2. 4.2.The elevated portion of the building and supporting foundation system have been designed to withstand the effects of wind and flood loads acting simultaneously on structural and nonstructural building components. Water-loading values used shall be those associated with the design flood. Wind-loading values shall be those required by this code.

    5. 5.Walls intended to break away under flood loads as specified in Item 3 or 4 have flood openings that meet the criteria in Section R322.2.2, Item 2.

    R322.3.5 Enclosed areas below design flood elevation.

    Enclosed areas below the design flood elevation shall be used solely for parking of vehicles, building access or storage.

    R322.3.5.1 Protection of building envelope.

    An exterior door that meets the requirements of Section R609 shall be installed at the top of stairs that provide access to the building and that are enclosed with walls designed to break away in accordance with Section R322.3.4.

    R322.3.6 Construction documents.

    The construction documents shall include documentation that is prepared and sealed by a registered design professional that the design and methods of construction to be used meet the applicable criteria of this section.

    R322.3.7 Tanks.

    Underground tanks shall be anchored to prevent flotation, collapse and lateral movement under conditions of the base flood. Above-ground tanks shall be installed at or above the elevation required in Section R322.3.2. Where elevated on platforms, the platforms shall be cantilevered from or knee braced to the building or shall be supported on foundations that conform to the requirements of Section R322.3.

    SECTIONR323
    STORM SHELTERS

    R323.1 General.

    This section applies to storm shelters where constructed as separate detached buildings or where constructed as safe rooms within buildings for the purpose of providing refuge from storms that produce high winds, such as tornados and hurricanes. In addition to other applicable requirements in this code, storm shelters shall be constructed in accordance with ICC/NSSA-500.

    SECTION324
    SOLAR ENERGY SYSTEMS

    R324.1 General.

    Solar energy systems shall comply with the provisions of this section.

    R324.2 Solar thermal systems.

    Solar thermal systems shall be designed and installed in accordance with Chapter 23 and the International Fire Code.

    R324.3 Photovoltaic systems.

    Photovoltaic systems shall be designed and installed in accordance with Sections R324.3.1 through R324.6.1 and NFPA 70. Inverters shall be listed and labeled in accordance with UL 1741. Systems connected to the utility grid shall use inverters listed for utility interaction.

    R324.3.1 Equipment listings.

    Photovoltaic panels and modules shall be listed and labeled in accordance with UL 1703.

    R324.4 Rooftop-mounted photovoltaic systems.

    Rooftop-mounted photovoltaic panel systems installed on or above the roof covering shall be designed and installed in accordance with Section R907.

    R324.4.1 Roof live load.

    Roof structures that provide support for photovoltaic panel systems shall be designed for applicable roof live load. The design of roof structures need not include roof live load in the areas covered by photovoltaic panel systems. Portions of roof structures not covered by photovoltaic panels shall be designed for roof live load. Roof structures that provide support for photo-voltaic panel systems shall be designed for live load, LR, for the load case where the photovoltaic panel system is not present.

    R324.5 Building-integrated photovoltaic systems.

    Building-integrated photovoltaic systems that serve as roof coverings shall be designed and installed in accordance with Section R905.

    R324.5.1 Photovoltaic shingles.

    Photovoltaic shingles shall comply with Section R905.16.

    R324.6 Ground-mounted photovoltaic systems.

    Ground-mounted photovoltaic systems shall be designed and installed in accordance with Section R301.

    R324.6.1 Fire separation distances.

    Ground-mounted photovoltaic systems shall be subject to the fire separation distance requirements determined by the local jurisdiction.

    SECTIONR325
    MEZZANINES

    R325.1 General.

    Mezzanines shall comply with Section R325.

    R325.2 Mezzanines.

    The clear height above and below mezzanine floor construction shall be not less than 7 feet (2134 mm).

    R325.3 Area limitation.

    The aggregate area of a mezzanine or mezzanines shall be not greater than one-third of the floor area of the room or space in which they are located. The enclosed portion of a room shall not be included in a determination of the floor area of the room in which the mezzanine is located.

    R325.4 Means of egress.

    The means of egress for mezzanines shall comply with the applicable provisions of Section R311.

    R325.5 Openness.

    Mezzanines shall be open and unobstructed to the room in which they are located except for walls not more than 36 inches (914 mm) in height, columns and posts.

    Exceptions:

    1. 1.Mezzanines or portions thereof are not required to be open to the room in which they are located, provided that the aggregate floor area of the enclosed space is not greater than 10 percent of the mezzanine area.

    2. 2.In buildings that are not more than two stories above grade plane and equipped throughout with an automatic sprinkler system in accordance with Section R313, a mezzanine shall not be required to be open to the room in which the mezzanine is located.

    SECTIONR326
    SWIMMING POOLS, SPAS AND HOT TUBS

    R326.1 General.

    The design and construction of pools and spas shall comply with the International Swimming Pool and Spa Code.

    CHAPTER4
    FOUNDATIONS  

    SECTIONR401
    GENERAL

    R401.1 Application.

    The provisions of this chapter shall control the design and construction of the foundation and foundation spaces for buildings. In addition to the provisions of this chapter, the design and construction of foundations in flood hazard areas as established by Table R301.2(1) shall meet the provisions of Section R322. Wood foundations shall be designed and installed in accordance with AWC PWF.

    Exception: The provisions of this chapter shall be permitted to be used for wood foundations only in the following situations:

    1. 1.In buildings that have no more than two floors and a roof.

    2. 2.Where interior basement and foundation walls are constructed at intervals not exceeding 50 feet (15 240 mm).

    Wood foundations in Seismic Design Category D0, D1 or D2 shall be designed in accordance with accepted engineering practice.

    R401.2 Requirements.

    Foundation construction shall be capable of accommodating all loads in accordance with Section R301 and of transmitting the resulting loads to the supporting soil. Fill soils that support footings and foundations shall be designed, installed and tested in accordance with accepted engineering practice. Gravel fill used as footings for wood and precast concrete foundations shall comply with Section R403.

    R401.3 Drainage.

    Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm) within the first 10 feet (3048 mm).

    Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152 mm) of fall within 10 feet (3048 mm), drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.

    R401.4 Soil tests.

    Where quantifiable data created by accepted soil science methodologies indicate expansive, compressible, shifting or other questionable soil characteristics are likely to be present, the building official shall determine whether to require a soil test to determine the soil’s characteristics at a particular location. This test shall be done by an approved agency using an approved method.

    R401.4.1 Geotechnical evaluation.

    In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1 shall be assumed.

    TABLE R401.4.1

    PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa

    CLASS OF MATERIALLOAD-BEARING PRESSURE (pounds per square foot)
    Crystalline bedrock12,000
    Sedimentary and foliated rock4,000
    Sandy gravel and/or gravel (GW and GP)3,000
    Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC)2,000
    Clay, sandy, silty clay, clayey silt, silt and sandy siltclay (CL, ML, MH and CH)1,500b

    For SI: 1 pound per square foot = 0.0479 kPa.

    1. a.Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.

    2. b.Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing capacity shall be determined by a soils investigation.

    R401.4.2 Compressible or shifting soil.

    Instead of a complete geotechnical evaluation, where top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to ensure stable moisture content in each active zone and shall not be used as fill or stabilized within each active zone by chemical, dewatering or presaturation.

    SECTIONR402
    MATERIALS

    R402.1 Wood foundations.

    Wood foundation systems shall be designed and installed in accordance with the provisions of this code.

    R402.1.1 Fasteners.

    Fasteners used below grade to attach plywood to the exterior side of exterior basement or crawl-space wall studs, or fasteners used in knee wall construction, shall be of Type 304 or 316 stainless steel. Fasteners used above grade to attach plywood and all lumber-to-lumber fasteners except those used in knee wall construction shall be of Type 304 or 316 stainless steel, silicon bronze, copper, hot-dipped galvanized (zinc coated) steel nails, or hot-tumbled galvanized (zinc coated) steel nails. Electro-galvanized steel nails and galvanized (zinc coated) steel staples shall not be permitted.

    R402.1.2 Wood treatment.

    All lumber and plywood shall be pressure-preservative treated and dried after treatment in accordance with AWPA U1 (Commodity Specification A, Use Category 4B and Section 5.2), and shall bear the label of an accredited agency. Where lumber and/or plywood is cut or drilled after treatment, the treated surface shall be field treated with copper naphthenate, the concentration of which shall contain a minimum of 2-percent copper metal, by repeated brushing, dipping or soaking until the wood absorbs no more preservative.

    R402.2 Concrete.

    Concrete shall have a minimum specified compressive strength of f ′c, as shown in Table R402.2. Concrete subject to moderate or severe weathering as indicated in Table R301.2(1) shall be air entrained as specified in Table R402.2. The maximum weight of fly ash, other pozzolans, silica fume, slag or blended cements that is included in concrete mixtures for garage floor slabs and for exterior porches, carport slabs and steps that will be exposed to deicing chemicals shall not exceed the percentages of the total weight of cementitious materials specified in Section 19.3.3.4 of ACI 318. Materials used to produce concrete and testing thereof shall comply with the applicable standards listed in Chapters 19 and 20 of ACI 318 or ACI 332.

    TABLE R402.2

    MINIMUM SPECIFIED COMPRESSIVE STRENGTH OF CONCRETE

    TYPE OR LOCATION OF CONCRETE CONSTRUCTIONMINIMUM SPECIFIED COMPRESSIVE STRENGTHa (fc)
    Weathering Potentialb
    NegligibleModerateSevere
    Basement walls, foundations and other concrete not exposed to the weather2,5002,5002,500c
    Basement slabs and interior slabs on grade, except garage floor slabs2,5002,5002,500c
    Basement walls, foundation walls, exterior walls and other vertical concrete work exposed to the weather2,5003,000d3,000d
    Porches, carport slabs and steps exposed to the weather, and garage floor slabs2,5003,000d, e, f3,500d, e, f

    For SI: 1 pound per square inch = 6.895 kPa.

    1. a.Strength at 28 days psi.

    2. b.See Table R301.2(1) for weathering potential.

    3. c.Concrete in these locations that is subject to freezing and thawing during construction shall be air-entrained concrete in accordance with Footnote d.

    4. d.Concrete shall be air-entrained. Total air content (percent by volume of concrete) shall be not less than 5 percent or more than 7 percent.

    5. e.See Section R402.2 for maximum cementitious materials content.

    6. f.For garage floors with a steel-troweled finish, reduction of the total air content (percent by volume of concrete) to not less than 3 percent is permitted if the specified compressive strength of the concrete is increased to not less than 4,000 psi.

    R402.2.1 Materials for concrete.

    Materials for concrete shall comply with the requirements of Section R608.5.1.

    R402.3 Precast concrete.

    Precast concrete foundations shall be designed in accordance with Section R404.5 and shall be installed in accordance with the provisions of this code and the manufacturer’s instructions.

    R402.3.1 Precast concrete foundation materials.

    Materials used to produce precast concrete foundations shall meet the following requirements.

    1. 1.All concrete used in the manufacture of precast concrete foundations shall have a minimum compressive strength of 5,000 psi (34 470 kPa) at 28 days. Concrete exposed to a freezing and thawing environment shall be air entrained with a minimum total air content of 5 percent.

    2. 2.Structural reinforcing steel shall meet the requirements of ASTM A 615, A 706 or A 996. The minimum yield strength of reinforcing steel shall be 40,000 psi (Grade 40) (276 MPa). Steel reinforcement for precast concrete foundation walls shall have a minimum concrete cover of 3/4 inch (19.1 mm).

    3. 3.Panel-to-panel connections shall be made with Grade II steel fasteners.

    4. 4.The use of nonstructural fibers shall conform to ASTM C 1116.

    5. 5.Grout used for bedding precast foundations placed upon concrete footings shall meet ASTM C 1107.

    R402.4 Masonry.

    Masonry systems shall be designed and installed in accordance with this chapter and shall have a minimum specified compressive strength of 1,500 psi (10.3 MPa).

    SECTIONR403
    FOOTINGS

    R403.1 General.

    All exterior walls shall be supported on continuous solid or fully grouted masonry or concrete footings, crushed stone footings, wood foundations, or other approved structural systems which shall be of sufficient design to accommodate all loads according to Section R301 and to transmit the resulting loads to the soil within the limitations as determined from the character of the soil. Footings shall be supported on undisturbed natural soils or engineered fill. Concrete footing shall be designed and constructed in accordance with the provisions of Section R403 or in accordance with ACI 332.

    TABLE R403.1(1)

    MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION (inches)a, b

    SNOW LOAD OR ROOF LIVE LOADSTORY AND TYPE OF STRUCTURE WITH LIGHT FRAMELOAD-BEARING VALUE OF SOIL (psf)
    150020002500300035004000
    20 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement18 × 614 × 612 × 612 × 612 × 612 × 6
    2 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space16 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—plus basement22 × 616 × 613 × 612 × 612 × 612 × 6
    3 story—slab-on-grade14 × 612 × 612 × 612 × 612 × 612 × 6
    3 story—with crawl space19 × 614 × 612 × 612 × 612 × 612 × 6
    3 story—plus basement25 × 819 × 615 × 613 × 612 × 612 × 6
    30 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space13 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement19 × 614 × 612 × 612 × 612 × 612 × 6
    2 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space17 × 613 × 612 × 612 × 612 × 612 × 6
    2 story—plus basement23 × 617 × 614 × 612 × 612 × 612 × 6
    3 story—slab-on-grade15 × 612 × 612 × 612 × 612 × 612 × 6
    3 story—with crawl space20 × 615 × 612 × 612 × 612 × 612 × 6
    3 story—plus basement26 × 820 × 616 × 613 × 612 × 612 × 6
    50 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space16 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement21 × 616 × 613 × 612 × 612 × 612 × 6
    2 story—slab-on-grade14 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space19 × 614 × 612 × 612 × 612 × 612 × 6
    2 story—plus basement25 × 719 × 615 × 612 × 612 × 612 × 6
    3 story—slab-on-grade17 × 613 × 612 × 612 × 612 × 612 × 6
    3 story—with crawl space22 × 617 × 613 × 612 × 612 × 612 × 6
    3 story—plus basement28 × 921 × 617 × 614 × 612 × 612 × 6
    70 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space18 × 613 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement24 × 718 × 614 × 612 × 612 × 612 × 6
    2 story—slab-on-grade16 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space21 × 616 × 613 × 612 × 612 × 612 × 6
    2 story—plus basement27 × 920 × 616 × 614 × 612 × 612 × 6
    3 story—slab-on-grade19 × 614 × 612 × 612 × 612 × 612 × 6
    3 story—with crawl space25 × 718 × 615 × 612 × 612 × 612 × 6
    3 story—plus basement30 × 1023 × 618 × 615 × 613 × 612 × 6

    For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

    1. a.Interpolation allowed. Extrapolation is not allowed.

    2. b.Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

    //cdn-codes.iccsafe.org/bundles/document/new_document_images/553/Tbl0001.jpg

    TABLE R403.1(2)

    MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS FOR LIGHT-FRAME CONSTRUCTION WITH BRICK VENEER (inches)a, b

    SNOW LOAD OR ROOF LIVE LOADSTORY AND TYPE OF STRUCTURE WITH BRICK VENEERLOAD-BEARING VALUE OF SOIL (psf)
    150020002500300035004000
    20 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space15 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement21 × 615 × 612 × 612 × 612 × 612 × 6
    2 story—slab-on-grade15 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space20 × 615 × 612 × 612 × 612 × 612 × 6
    2 story—plus basement26 × 820 × 616 × 613 × 612 × 612 × 6
    3 story—slab-on-grade20 × 615 × 612 × 612 × 612 × 612 × 6
    3 story—with crawl space26 × 819 × 615 × 613 × 612 × 612 × 6
    3 story—plus basement32 × 1124 × 719 × 616 × 614 × 612 × 6
    30 psf1 story—slab-on-grade12 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space16 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement22 × 616 × 613 × 612 × 612 × 612 × 6
    2 story—slab-on-grade16 × 612 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space22 × 616 × 613 × 612 × 612 × 612 × 6
    2 story—plus basement27 × 921 × 616 × 614 × 612 × 612 × 6
    3 story—slab-on-grade21 × 616 × 613 × 612 × 612 × 612 × 6
    3 story—with crawl space27 × 820 × 616 × 613 × 612 × 612 × 6
    3 story—plus basement33 × 1124 × 720 × 616 × 614 × 612 × 6
    50 psf1 story—slab-on-grade13 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space18 × 614 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement24 × 718 × 614 × 612 × 612 × 612 × 6
    2 story—slab-on-grade18 × 614 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space24 × 718 × 614 × 612 × 612 × 612 × 6
    2 story—plus basement29 × 1022 × 618 × 615 × 613 × 612 × 6
    3 story—slab-on-grade27 × 718 × 613 × 612 × 612 × 612 × 6
    3 story—with crawl space29 × 922 × 617 × 614 × 612 × 612 × 6
    3 story—plus basement35 × 1226 × 821 × 617 × 615 × 613 × 6
    70 psf1 story—slab-on-grade15 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space20 × 615 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement26 × 820 × 616 × 613 × 612 × 612 × 6
    2 story—slab-on grade20 × 615 × 612 × 612 × 612 × 612 × 6
    2 story—with crawl space26 × 819 × 615 × 613 × 612 × 612 × 6
    2 story—plus basement32 × 1124 × 719 × 616 × 614 × 612 × 6
    3 story—slab-on-grade26 × 819 × 615 × 613 × 612 × 612 × 6
    3 story—with crawl space31 × 1123 × 719 × 616 × 613 × 612 × 6
    3 story—plus basement37 × 1328 × 922 × 618 × 616 × 614 × 6

    For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

    1. a.Interpolation allowed. Extrapolation is not allowed.

    2. b.Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

    //cdn-codes.iccsafe.org/bundles/document/new_document_images/553/Tbl0002.jpg

    TABLE R403.1(3)

    MINIMUM WIDTH AND THICKNESS FOR CONCRETE FOOTINGS WITH CAST-IN-PLACE CONCRETE OR FULLY GROUTED MASONRY WALL CONSTRUCTION (inches)a, b

    SNOW LOAD OR ROOF LIVE LOADSTORY AND TYPE OF STRUCTURE WITH CMULOAD-BEARING VALUE OF SOIL (psf)
    150020002500300035004000
    20 psf1 story—slab-on-grade14 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space19 × 614 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement25 × 819 × 615 × 613 × 612 × 612 × 6
    2 story—slab-on-grade23 × 718 × 614 × 612 × 612 × 612 × 6
    2 story—with crawl space29 × 922 × 617 × 614 × 612 × 612 × 6
    2 story—plus basement35 × 1226 × 821 × 617 × 615 × 613 × 6
    3 story—slab-on-grade32 × 1124 × 719 × 616 × 614 × 612 × 6
    3 story—with crawl space38 × 1428 × 923 × 619 × 616 × 614 × 6
    3 story—plus basement43 × 1733 × 1126 × 822 × 619 × 616 × 6
    30 psf1 story—slab-on-grade15 × 612 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space20 × 615 × 612 × 612 × 612 × 612 × 6
    1 story—plus basement26 × 820 × 616 × 613 × 612 × 612 × 6
    2 story—slab-on-grade24 × 718 × 615 × 612 × 612 × 612 × 6
    2 story—with crawl space30 × 1022 × 618 × 615 × 613 × 612 × 6
    2 story—plus basement36 × 1327 × 821 × 618 × 615 × 613 × 6
    3 story—slab-on-grade33 × 1225 × 720 × 617 × 614 × 612 × 6
    3 story—with crawl space39 × 1429 × 923 × 719 × 617 × 614 × 6
    3 story—plus basement44 × 1733 × 1227 × 822 × 619 × 617 × 6
    50 psf1 story—slab-on-grade17 × 613 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space22 × 617 × 613 × 612 × 612 × 612 × 6
    1 story—plus basement28 × 921 × 617 × 614 × 612 × 612 × 6
    2 story—slab-on-grade27 × 820 × 616 × 613 × 612 × 612 × 6
    2 story—with crawl space32 × 1124 × 719 × 616 × 614 × 612 × 6
    2 story—plus basement38 × 1428 × 923 × 619 × 616 × 614 × 6
    3 story—slab-on-grade35 × 1327 × 821 × 618 × 615 × 613 × 6
    3 story—with crawl space41 × 1531 × 1024 × 720 × 617 × 615 × 6
    3 story—plus basement47 × 1835 × 1228 × 923 × 720 × 617 × 6
    70 psf1 story—slab-on-grade19 × 614 × 612 × 612 × 612 × 612 × 6
    1 story—with crawl space25 × 718 × 615 × 612 × 612 × 612 × 6
    1 story—plus basement30 × 1023 × 618 × 615 × 613 × 612 × 6
    2 story—slab-on-grade29 × 922 × 617 × 614 × 612 × 612 × 6
    2 story—with crawl space34 × 1226 × 821 × 617 × 615 × 613 × 6
    2 story—plus basement40 × 1530 × 1024 × 720 × 617 × 615 × 6
    3 story—slab-on-grade38 × 1428 × 923 × 619 × 616 × 614 × 6
    3 story—with crawl space43 × 1632 × 1126 × 821 × 618 × 616 × 6
    3 story—plus basement49 × 1937 × 1329 × 1024 × 721 × 618 × 6

    For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

    1. a.Interpolation allowed. Extrapolation is not allowed.

    2. b.Based on 32-foot-wide house with load-bearing center wall that carries half of the tributary attic, and floor framing. For every 2 feet of adjustment to the width of the house add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).

    //cdn-codes.iccsafe.org/bundles/document/new_document_images/553/Tbl0003.jpg

    For SI: 1 inch = 25.4 mm.

    W = Width of footing, T = Thickness of footing and P = Projection per Section R403.1.1

    NOTES:

    1. a.See Section R404.3 for sill requirements.

    2. b.See Section R403.1.6 for sill attachment.

    3. c.See Section R506.2.3 for vapor barrier requirements.

    4. d.See Section R403.1 for base.

    5. e.See Figure R403.1.3 for additional footing requirements for structures in SDC D0, D1 and D2 and townhouses in SDC C.

    6. f.See Section R408 for under-floor ventilation and access requirements.

    FIGURE R403.1(1)

    PLAIN CONCRETE FOOTINGS WITH MASONRY AND CONCRETE STEM WALLS IN SDC A, B AND Ca, b, c, d, e, f

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254.

    FIGURE R403.1(2)

    PERMANENT WOOD FOUNDATION BASEMENT WALL SECTION

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mil = 0.0254 mm.

    FIGURE R403.1(3)

    PERMANENT WOOD FOUNDATION CRAWL SPACE SECTION

    R403.1.1 Minimum size.

    The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable. The footing width shall be based on the load-bearing value of the soil in accordance with Table R401.4.1. Footing projections, P, shall be not less than 2 inches (51 mm) and shall not exceed the thickness of the footing. Footing thickness and projection for fireplaces shall be in accordance with Section R1001.2. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table R401.4.1. Footings for wood foundations shall be in accordance with the details set forth in Section R403.2, and Figures R403.1(2) and R403.1(3).

    R403.1.2 Continuous footing in Seismic Design Categories D0, D1 and D2.

    Exterior walls of buildings located in Seismic Design Categories D0, D1 and D2 shall be supported by continuous solid or fully grouted masonry or concrete footings. Other footing materials or systems shall be designed in accordance with accepted engineering practice. All required interior braced wall panels in buildings located in Seismic Design Categories D0, D1 and D2 with plan dimensions greater than 50 feet (15 240 mm) shall be supported by continuous solid or fully grouted masonry or concrete footings in accordance with Section R403.1.3.4, except for two-story buildings in Seismic Design Category D2, in which all braced wall panels, interior and exterior, shall be supported on continuous foundations.

    Exception: Two-story buildings shall be permitted to have interior braced wall panels supported on continuous foundations at intervals not exceeding 50 feet (15 240 mm) provided that:

    1. 1.The height of cripple walls does not exceed 4 feet (1219 mm).

    2. 2.First-floor braced wall panels are supported on doubled floor joists, continuous blocking or floor beams.

    3. 3.The distance between bracing lines does not exceed twice the building width measured parallel to the braced wall line.

    R403.1.3 Footing and stem wall reinforcing in Seismic Design Categories D0, D1, and D2.

    Concrete footings located in Seismic Design Categories D0, D1 and D2, as established in Table R301.2(1), shall have minimum reinforcement in accordance with this section and Figure R403.1.3. Reinforcement shall be installed with support and cover in accordance with Section R403.1.3.5.

    W = Width of footing, T = Thickness of footing and P = Projection per Section R403.1.1

    NOTES:

    1. a.See Section R404.3 for sill requirements.

    2. b.See Section R403.1.6 for sill attachment.

    3. c.See Section R506.2.3 for vapor barrier requirements.

    4. d.See Section R403.1 for base.

    5. e.See Section R408 for under-floor ventilation and access requirements.

    6. f.See Section R403.1.3.5 for reinforcement requirements.

    FIGURE R403.1.3

    REINFORCED CONCRETE FOOTINGS AND MASONRY AND CONCRETE STEM WALLS IN SDC D0, D1 AND D2a, b, c, d, e, f,

    R403.1.3.1 Concrete stem walls with concrete footings.

    In Seismic Design Categories D0, D1 and D2 where a construction joint is created between a concrete footing and a concrete stem wall, a minimum of one No. 4 vertical bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall have a standard hook and extend to the bottom of the footing and shall have support and cover as specified in Section R403.1.3.5.3 and extend a minimum of 14 inches (357 mm) into the stem wall. Standard hooks shall comply with Section R608.5.4.5. A minimum of one No. 4 horizontal bar shall be installed within 12 inches (305 mm) of the top of the stem wall and one No. 4 horizontal bar shall be located 3 to 4 inches (76 mm to 102 mm) from the bottom of the footing.

    R403.1.3.2 Masonry stem walls with concrete footings.

    In Seismic Design Categories D0, D1 and D2 where a masonry stem wall is supported on a concrete footing, a minimum of one No. 4 vertical bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall have a standard hook and extend to the bottom of the footing and shall have support and cover as specified in Section R403.1.3.5.3 and extend a minimum of 14 inches (357 mm) into the stem wall. Standard hooks shall comply with Section R608.5.4.5. A minimum of one No. 4 horizontal bar shall be installed within 12 inches (305 mm) of the top of the wall and one No. 4 horizontal bar shall be located 3 to 4 inches (76 mm to 102 mm) from the bottom of the footing. Masonry stem walls shall be solid grouted.

    R403.1.3.3 Slabs-on-ground with turned-down footings.

    In Seismic Design Categories D0, D1 and D2, slabs on ground cast monolithically with turned-down footings shall have a minimum of one No. 4 bar at the top and the bottom of the footing or one No. 5 bar or two No. 4 bars in the middle third of the footing depth.

    Where the slab is not cast monolithically with the footing, No. 3 or larger vertical dowels with standard hooks on each end shall be installed at not more than 4 feet (1219 mm) on center in accordance with Figure R403.1.3, Detail 2. Standard hooks shall comply with Section R608.5.4.5.

    R403.1.3.4 Interior bearing and braced wall panel footings in Seismic Design Categories D0, D1 and D2.

    In Seismic Design Categories D0, D1 and D2, interior footings supporting bearing walls or braced wall panels, and cast monolithically with a slab on grade, shall extend to a depth of not less than 12 inches (305 mm) below the top of the slab.

    R403.1.3.5 Reinforcement.

    Footing and stem wall reinforcement shall comply with Sections R403.1.3.5.1 through R403.1.3.5.4.

    R403.1.3.5.1 Steel reinforcement.

    Steel reinforcement shall comply with the requirements of ASTM A 615, A 706 or A 996. ASTM A 996 bars produced from rail steel shall be Type R. The minimum yield strength of reinforcing steel shall be 40,000 psi (Grade 40) (276 MPa).

    R403.1.3.5.2 Location of reinforcement in wall.

    The center of vertical reinforcement in stem walls shall be located at the centerline of the wall. Horizontal and vertical reinforcement shall be located in footings and stem walls to provide the minimum cover required by Section R403.1.3.5.3.

    R403.1.3.5.3 Support and cover.

    Reinforcement shall be secured in the proper location in the forms with tie wire or other bar support system to prevent displacement during the concrete placement operation. Steel reinforcement in concrete cast against the earth shall have a minimum cover of 3 inches (75 mm). Minimum cover for reinforcement in concrete cast in removable forms that will be exposed to the earth or weather shall be 11/2 inches (38 mm) for No. 5 bars and smaller, and 2 inches (50 mm) for No. 6 bars and larger. For concrete cast in removable forms that will not be exposed to the earth or weather, and for concrete cast in stay-in-place forms, minimum cover shall be 3/4 inch (19 mm).

    R403.1.3.5.4 Lap splices.

    Vertical and horizontal reinforcement shall be the longest lengths practical. Where splices are necessary in reinforcement, the length of lap splice shall be in accordance with Table R608.5.4.(1) and Figure R608.5.4(1). The maximum gap between noncontact parallel bars at a lap splice shall not exceed the smaller of one-fifth the required lap length and 6 inches (152 mm) [see Figure R608.5.4(1)].

    R403.1.3.6 Isolated concrete footings.

    In detached one- and two-family dwellings that are three stories or less in height and constructed with stud bearing walls, isolated plain concrete footings supporting columns or pedestals are permitted.

    R403.1.4 Minimum depth.

    Exterior footings shall be placed not less than 12 inches (305 mm) below the undisturbed ground surface. Where applicable, the depth of footings shall also conform to Sections R403.1.4.1 through R403.1.4.2.

    R403.1.4.1 Frost protection.

    Except where otherwise protected from frost, foundation walls, piers and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:

    1. 1.Extended below the frost line specified in Table R301.2.(1).

    2. 2.Constructed in accordance with Section R403.3.

    3. 3.Constructed in accordance with ASCE 32.

    4. 4.Erected on solid rock.

    Exceptions:

    1. 1.Protection of freestanding accessory structures with an area of 600 square feet (56 m2) or less, of light-frame construction, with an eave height of 10 feet (3048 mm) or less shall not be required.

    2. 2.Protection of freestanding accessory structures with an area of 400 square feet (37 m2) or less, of other than light-frame construction, with an eave height of 10 feet (3048 mm) or less shall not be required.

    3. 3.Decks not supported by a dwelling need not be provided with footings that extend below the frost line.

    Footings shall not bear on frozen soil unless the frozen condition is permanent.

    R403.1.5 Slope.

    The top surface of footings shall be level. The bottom surface of footings shall not have a slope exceeding one unit vertical in 10 units horizontal (10-percent slope). Footings shall be stepped where it is necessary to change the elevation of the top surface of the footings or where the slope of the bottom surface of the footings will exceed one unit vertical in 10 units horizontal (10-percent slope).

    R403.1.6 Foundation anchorage.

    Wood sill plates and wood walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

    Cold-formed steel framing shall be anchored directly to the foundation or fastened to wood sill plates anchored to the foundation. Anchorage of cold-formed steel framing and sill plates supporting cold-formed steel framing shall be in accordance with this section and Section R505.3.1 or R603.3.1.

    Wood sole plates at all exterior walls on monolithic slabs, wood sole plates of braced wall panels at building interiors on monolithic slabs and all wood sill plates shall be anchored to the foundation with minimum 1/2-inch-diameter (12.7 mm) anchor bolts spaced a maximum of 6 feet (1829 mm) on center or approved anchors or anchor straps spaced as required to provide equivalent anchorage to 1/2-inch-diameter (12.7 mm) anchor bolts. Bolts shall extend a minimum of 7 inches (178 mm) into concrete or grouted cells of concrete masonry units. The bolts shall be located in the middle third of the width of the plate. A nut and washer shall be tightened on each anchor bolt. There shall be a minimum of two bolts per plate section with one bolt located not more than 12 inches (305 mm) or less than seven bolt diameters from each end of the plate section. Interior bearing wall sole plates on monolithic slab foundation that are not part of a braced wall panel shall be positively anchored with approved fasteners. Sill plates and sole plates shall be protected against decay and termites where required by Sections R317 and R318.

    Exceptions:

    1. 1.Walls 24 inches (610 mm) total length or shorter connecting offset braced wall panels shall be anchored to the foundation with a minimum of one anchor bolt located in the center third of the plate section and shall be attached to adjacent braced wall panels at corners as shown in Item 9 of Table R602.3(1).

    2. 2.Connection of walls 12 inches (305 mm) total length or shorter connecting offset braced wall panels to the foundation without anchor bolts shall be permitted. The wall shall be attached to adjacent braced wall panels at corners as shown in Item 9 of Table R602.3(1).

    R403.1.6.1 Foundation anchorage in Seismic Design Categories C, D0, D1 and D2.

    In addition to the requirements of Section R403.1.6, the following requirements shall apply to wood light-frame structures in Seismic Design Categories D0, D1 and D2 and wood light-frame townhouses in Seismic Design Category C.

    1. 1.Plate washers conforming to Section R602.11.1 shall be provided for all anchor bolts over the full length of required braced wall lines except where approved anchor straps are used. Properly sized cut washers shall be permitted for anchor bolts in wall lines not containing braced wall panels.

    2. 2.Interior braced wall plates shall have anchor bolts spaced at not more than 6 feet (1829 mm) on center and located within 12 inches (305 mm) of the ends of each plate section when supported on a continuous foundation.

    3. 3.Interior bearing wall sole plates shall have anchor bolts spaced at not more than 6 feet (1829 mm) on center and located within 12 inches (305 mm) of the ends of each plate section when supported on a continuous foundation.

    4. 4.The maximum anchor bolt spacing shall be 4 feet (1219 mm) for buildings over two stories in height.

    5. 5.Stepped cripple walls shall conform to Section R602.11.2.

    6. 6.Where continuous wood foundations in accordance with Section R404.2 are used, the force transfer shall have a capacity equal to or greater than the connections required by Section R602.11.1 or the braced wall panel shall be connected to the wood foundations in accordance with the braced wall panel-to-floor fastening requirements of Table R602.3(1).

    R403.1.7 Footings on or adjacent to slopes.

    The placement of buildings and structures on or adjacent to slopes steeper than one unit vertical in three units horizontal (33.3-percent slope) shall conform to Sections R403.1.7.1 through R403.1.7.4.

    R403.1.7.1 Building clearances from ascending slopes.

    In general, buildings below slopes shall be set a sufficient distance from the slope to provide protection from slope drainage, erosion and shallow failures. Except as provided in Section R403.1.7.4 and Figure R403.1.7.1, the following criteria will be assumed to provide this protection. Where the existing slope is steeper than one unit vertical in one unit horizontal (100-percent slope), the toe of the slope shall be assumed to be at the intersection of a horizontal plane drawn from the top of the foundation and a plane drawn tangent to the slope at an angle of 45 degrees (0.79 rad) to the horizontal. Where a retaining wall is constructed at the toe of the slope, the height of the slope shall be measured from the top of the wall to the top of the slope.

    For SI: 1 foot = 304.8 mm.

    FIGURE R403.1.7.1

    FOUNDATION CLEARANCE FROM SLOPES

    R403.1.7.2 Footing setback from descending slope surfaces.

    Footings on or adjacent to slope surfaces shall be founded in material with an embedment and setback from the slope surface sufficient to provide vertical and lateral support for the footing without detrimental settlement. Except as provided for in Section R403.1.7.4 and Figure R403.1.7.1, the following setback is deemed adequate to meet the criteria. Where the slope is steeper than one unit vertical in one unit horizontal (100-percent slope), the required setback shall be measured from an imaginary plane 45 degrees (0.79 rad) to the horizontal, projected upward from the toe of the slope.

    R403.1.7.3 Foundation elevation.

    On graded sites, the top of any exterior foundation shall extend above the elevation of the street gutter at point of discharge or the inlet of an approved drainage device a minimum of 12 inches (305 mm) plus 2 percent. Alternate elevations are permitted subject to the approval of the building official, provided it can be demonstrated that required drainage to the point of discharge and away from the structure is provided at all locations on the site.

    R403.1.7.4 Alternate setbacks and clearances.

    Alternate setbacks and clearances are permitted, subject to the approval of the building official. The building official is permitted to require an investigation and recommendation of a qualified engineer to demonstrate that the intent of this section has been satisfied. Such an investigation shall include consideration of material, height of slope, slope gradient, load intensity and erosion characteristics of slope material.

    R403.1.8 Foundations on expansive soils.

    Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808.6 of the International Building Code.

    Exception: Slab-on-ground and other foundation systems which have performed adequately in soil conditions similar to those encountered at the building site are permitted subject to the approval of the building official.

    R403.1.8.1 Expansive soils classifications.

    Soils meeting all four of the following provisions shall be considered expansive, except that tests to show compliance with Items 1, 2 and 3 shall not be required if the test prescribed in Item 4 is conducted:

    1. 1.Plasticity Index (PI) of 15 or greater, determined in accordance with ASTM D 4318.

    2. 2.More than 10 percent of the soil particles pass a No. 200 sieve (75 µm), determined in accordance with ASTM D 422.

    3. 3.More than 10 percent of the soil particles are less than 5 micrometers in size, determined in accordance with ASTM D 422.

    4. 4.Expansion Index greater than 20, determined in accordance with ASTM D 4829.

    R403.2 Footings for wood foundations.

    Footings for wood foundations shall be in accordance with Figures R403.1(2) and R403.1(3). Gravel shall be washed and well graded. The maximum size stone shall not exceed 3/4 inch (19.1 mm). Gravel shall be free from organic, clayey or silty soils. Sand shall be coarse, not smaller than 1/16-inch (1.6 mm) grains and shall be free from organic, clayey or silty soils. Crushed stone shall have a maximum size of 1/2 inch (12.7 mm).

    R403.3 Frost-protected shallow foundations.

    For buildings where the monthly mean temperature of the building is maintained at a minimum of 64°F (18°C), footings are not required to extend below the frost line when protected from frost by insulation in accordance with Figure R403.3(1) and Table R403.3(1). Foundations protected from frost in accordance with Figure R403.3(1) and Table R403.3(1) shall not be used for unheated spaces such as porches, utility rooms, garages and carports, and shall not be attached to basements or crawl spaces that are not maintained at a minimum monthly mean temperature of 64°F (18°C).

    Materials used below grade for the purpose of insulating footings against frost shall be labeled as complying with ASTM C 578.

    For SI: 1 inch = 25.4 mm.

    1. a.See Table R403.3(1) for required dimensions and R-values for vertical and horizontal insulation and minimum footing depth.

    FIGURE R403.3(1)

    INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGS

    TABLE R403.3(1)

    MINIMUM FOOTING DEPTH AND INSULATION REQUIREMENTS FOR FROST-PROTECTED FOOTINGS IN HEATED BUILDINGSa

    AIR FREEZING INDEX (°F-days)bMINIMUM FOOTING DEPTH, D (inches)VERTICAL INSULATION R-VALUEc, dHORIZONTAL INSULATION R-VALUEc, eHORIZONTAL INSULATION DIMENSIONS PER FIGURE R403.3(1) (inches)
    Along wallsAt cornersABC
    1,500 or less124.5Not requiredNot requiredNot requiredNot requiredNot required
    2,000145.6Not requiredNot requiredNot requiredNot requiredNot required
    2,500166.71.74.9122440
    3,000167.86.58.6122440
    3,500169.08.011.2243060
    4,0001610.110.513.1243660

    For SI: 1 inch = 25.4 mm, °C = [(°F) - 32]/1.8.

    1. a.Insulation requirements are for protection against frost damage in heated buildings. Greater values may be required to meet energy conservation standards.

    2. b.See Figure R403.3(2) or Table R403.3(2) for Air Freezing Index values.

    3. c.Insulation materials shall provide the stated minimum R-values under long-term exposure to moist, below-ground conditions in freezing climates. The following R-values shall be used to determine insulation thicknesses required for this application: Type II expanded polystyrene-2.4R per inch; Type IV extruded polystyrene-4.5R per inch; Type VI extruded polystyrene-4.5R per inch; Type IX expanded polystyrene-3.2R per inch; Type X extruded polystyrene-4.5R per inch.

    4. d.Vertical insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.

    5. e.Horizontal insulation shall be expanded polystyrene insulation or extruded polystyrene insulation.

    For SI: °C = [(°F) -32]/1.8.

    Note: The air-freezing index is defined as cumulative degree days below 32°F. It is used as a measure of the combined magnitude and duration of air temperature below freezing. The index was computed over a 12-month period (July-June) for each of the 3,044 stations used in the above analysis. Dates from the 1951-80 period were fitted to a Weibull probability distribution to produce an estimate of the 100-year return period.

    FIGURE R403.3(2)

    AIR-FREEZING INDEX AN ESTIMATE OF THE 100-YEAR RETURN PERIOD

    TABLE R403.3(2)

    AIR-FREEZING INDEX FOR U.S. LOCATIONS BY COUNTY

    STATEAIR-FREEZING INDEX
    1500 or less20002500300035004000
    AlabamaAll counties
    AlaskaKetchikan Gateway, Prince of Wales-Outer Ketchikan (CA), Sitka, Wrangell-Petersburg (CA)Aleutians West (CA), Haines, Juneau, Skagway-Hoonah-Angoon (CA), YakutatAll counties not listed
    ArizonaAll counties
    ArkansasAll counties
    CaliforniaAll counties not listedNevada, Sierra
    ColoradoAll counties not listedArchuleta, Custer, Fremont, Huerfano, Las Animas, Ouray, Pitkin, San MiguelClear Creek, Conejos, Costilla, Dolores, Eagle, La Plata, Park, Routt, San Juan, SummitAlamosa, Grand, Jackson, Larimer, Moffat, Rio Blanco, Rio GrandeChaffee, Gunnison, Lake, SaguacheHinsdale, Mineral
    ConnecticutAll counties not listedHartford, Litchfield
    DelawareAll counties
    District of ColumbiaAll counties
    FloridaAll counties
    GeorgiaAll counties
    HawaiiAll counties
    IdahoAll counties not listedAdams, Bannock, Blaine, Clearwater, Idaho, Lincoln, Oneida, Power, Valley, WashingtonBingham, Bonneville, Camas, Caribou, Elmore, Franklin, Jefferson, Madison, TetonBear Lake, Butte, Custer, Fremont, LemhiClark
    IllinoisAll counties not listedBoone, Bureau, Cook, Dekalb, DuPage, Fulton, Grundy, Henderson, Henry, Iroquois, Jo Daviess, Kane, Kankakee, Kendall, Knox, La Salle, Lake, Lee, Livingston, Marshall, Mason, McHenry, McLean, Mercer, Peoria, Putnam, Rock Island, Stark, Tazewell, Warren, Whiteside, Will, WoodfordCarroll, Ogle, Stephenson, Winnebago
    IndianaAll counties not listedAllen, Benton, Cass, Fountain, Fulton, Howard, Jasper, Kosciusko, La Porte, Lake, Marshall, Miami, Newton, Porter, Pulaski, Starke, Steuben, Tippecanoe, Tipton, Wabash, Warren, White
    IowaAppanoose, Davis, Fremont, Lee, Van BurenAll counties not listedAllamakee, Black Hawk, Boone, Bremer, Buchanan, Buena Vista, Butler, Calhoun, Cerro Gordo, Cherokee, Chickasaw, Clay, Clayton, Delaware, Dubuque, Fayette, Floyd, Franklin, Grundy, Hamilton, Hancock, Hardin, Humboldt, Ida, Jackson, Jasper, Jones, Linn, Marshall, Palo Alto, Plymouth, Pocahontas, Poweshiek, Sac, Sioux, Story, Tama, Webster, Winnebago, Woodbury, Worth, WrightDickinson, Emmet, Howard, Kossuth, Lyon, Mitchell, O'Brien, Osceola, Winneshiek
    KansasAll counties
    KentuckyAll counties
    LouisianaAll counties
    MaineYorkKnox, Lincoln, SagadahocAndroscoggin, Cumberland, Hancock, Kennebec, Waldo, WashingtonAroostook, Franklin, Oxford, Penobscot, Piscataquis, Somerset
    MarylandAll counties
    MassachusettsAll counties not listedBerkshire, Franklin, Hampden, Worcester
    MichiganBerrien, Branch, Cass, Kalamazoo, Macomb, Ottawa, St. Clair, St. JosephAll counties not listedAlger, Charlevoix, Cheboygan, Chippewa, Crawford, Delta, Emmet, Iosco, Kalkaska, Lake, Luce, Mackinac, Menominee, Missaukee, Montmorency, Ogemaw, Osceola, Otsego, Roscommon, Schoolcraft, WexfordBaraga, Dickinson, Iron, Keweenaw, MarquetteGogebic, Houghton, Ontonagon
    MinnesotaHouston, WinonaAll counties not listedAitkin, Big Stone, Carlton, Crow Wing, Douglas, Itasca, Kanabec, Lake, Morrison, Pine, Pope, Stearns, Stevens, Swift, Todd, WadenaBecker, Beltrami, Cass, Clay, Clearwater, Grant, Hubbard, Kittson, Koochiching, Lake of the Woods, Mahnomen, Marshall, Norman, Otter Tail, Pennington, Polk, Red Lake, Roseau, St. Louis, Traverse, Wilkin
    MississippiAll counties
    MissouriAll counties not listedAtchison, Mercer, Nodaway, Putnam
    MontanaMineralBroadwater, Golden Valley, Granite, Lake, Lincoln, Missoula, Ravalli, Sanders, Sweet GrassBig Horn, Carbon, Jefferson, Judith Basin, Lewis and Clark, Meagher, Musselshell, Powder River, Powell, Silver Bow, Stillwater, WestlandCarter, Cascade, Deer Lodge, Falcon, Fergus, Flathead, Gallanting, Glacier, Madison, Park, Petroleum, Ponder, Rosebud, Teton, Treasure, YellowstoneBeaverhead, Blaine, Chouteau, Custer, Dawson, Garfield, Liberty, McCone, Prairie, Toole, WibauxDaniels, Hill, Phillips, Richland, Roosevelt, Sheridan, Valley
    NebraskaAdams, Banner, Chase, Cheyenne, Clay, Deuel, Dundy, Fillmore, Franklin, Frontier, Furnas, Gage, Garden, Gosper, Harlan, Hayes, Hitchcock, Jefferson, Kimball, Morrill, Nemaha, Nuckolls, Pawnee, Perkins, Phelps, Red Willow, Richardson, Saline, Scotts Bluff, Seward, Thayer, WebsterAll counties not listedBoyd, Burt, Cedar, Cuming, Dakota, Dixon, Dodge, Knox, Thurston
    NevadaAll counties not listedElko, Eureka, Nye, Washoe, White Pine
    New HampshireAll counties not listedCarroll, Coos, Grafton
    New JerseyAll counties
    New MexicoAll counties not listedRio ArribaColfax, Mora, Taos
    New YorkAlbany, Bronx, Cayuga, Columbia, Cortland, Dutchess, Genessee, Kings, Livingston, Monroe, Nassau, New York, Niagara, Onondaga, Ontario, Orange, Orleans, Putnam, Queens, Richmond, Rockland, Seneca, Suffolk, Wayne, Westchester, YatesAll counties not listedClinton, Essex, Franklin, Hamilton, Herkimer, Jefferson, Lewis, St. Lawrence, Warren
    North CarolinaAll counties
    North DakotaBillings, BowmanAdams, Dickey, Golden Valley, Hettinger, LaMoure, Oliver, Ransom, Sargent, Sioux, Slope, StarkAll counties not listed
    OhioAll counties not listedAshland, Crawford, Defiance, Holmes, Huron, Knox, Licking, Morrow, Paulding, Putnam, Richland, Seneca, Williams
    OklahomaAll counties
    OregonAll counties not listedBaker, Crook, Grant, Harney
    PennsylvaniaAll counties not listedBerks, Blair, Bradford, Cambria, Cameron, Centre, Clarion, Clearfield, Clinton, Crawford, Elk, Forest, Huntingdon, Indiana, Jefferson, Lackawanna, Lycoming, McKean, Pike, Potter, Susquehanna, Tioga, Venango, Warren, Wayne, Wyoming
    Rhode IslandAll counties
    South CarolinaAll counties
    South DakotaBennett, Custer, Fall River, Lawrence, Mellette, Shannon, Todd, TrippBon Homme, Charles Mix, Davison, Douglas, Gregory, Jackson, Jones, LymanAll counties not listedBeadle, Brookings, Brown, Campbell, Codington, Corson, Day, Deuel, Edmunds, Faulk, Grant, Hamlin, Kingsbury, Marshall, McPherson, Perkins, Roberts, Spink, Walworth
    TennesseeAll counties
    TexasAll counties
    UtahAll counties not listedBox Elder, Morgan, WeberGarfield, Salt Lake, SummitCarbon, Daggett, Duchesne, Rich, Sanpete, Uintah, Wasatch
    VermontBennington, Grand Isle, Rutland, WindhamAddison, Chittenden, Franklin, Orange, Washington, WindsorCaledonia, Essex, Lamoille, Orleans
    VirginiaAll counties
    WashingtonAll counties not listedChelan, Douglas, Ferry, Okanogan
    West VirginiaAll counties
    WisconsinKenosha, Kewaunee, Racine, Sheboygan, WalworthAll counties not listedAshland, Barron, Burnett, Chippewa, Clark, Dunn, Eau Claire, Florence, Forest, Iron, Jackson, La Crosse, Langlade, Marathon, Monroe, Pepin, Polk, Portage, Price, Rust, St. Croix, Taylor, Trempealeau, Vilas, WoodBayfield, Douglas, Lincoln, Oneida, Sawyer, Washburn
    WyomingGoshen, PlatteConverse, Crook, Laramie, NiobraraCampbell, Carbon, Hot Springs, Johnson, Natrona, Sheridan, Uinta, WestonAlbany, Big Horn, Park, WashakieFremont, TetonLincoln, Sublette, Sweetwater

    For SI: 1 inch = 25.4 mm.

    1. a.See Table R403.3(1) for required dimensions and R-values for vertical and horizontal insulation.

    FIGURE R403.3(3)

    INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS ADJACENT TO UNHEATED SLAB-ON-GROUND STRUCTURE

    FIGURE R403.3(4)

    INSULATION PLACEMENT FOR FROST-PROTECTED FOOTINGS ADJACENT TO HEATED STRUCTURE

    R403.3.1 Foundations adjoining frost-protected shallow foundations.

    Foundations that adjoin frost-protected shallow foundations shall be protected from frost in accordance with Section R403.1.4.

    R403.3.1.1 Attachment to unheated slab-on-ground structure.

    Vertical wall insulation and horizontal insulation of frost-protected shallow foundations that adjoin a slab-on-ground foundation that does not have a monthly mean temperature maintained at a minimum of 64°F (18°C) shall be in accordance with Figure R403.3(3) and Table R403.3(1). Vertical wall insulation shall extend between the frost-protected shallow foundation and the adjoining slab foundation. Required horizontal insulation shall be continuous under the adjoining slab foundation and through any foundation walls adjoining the frost- protected shallow foundation. Where insulation passes through a foundation wall, it shall be either of a type complying with this section and having bearing capacity equal to or greater than the structural loads imposed by the building, or the building shall be designed and constructed using beams, lintels, cantilevers or other means of transferring building loads such that the structural loads of the building do not bear on the insulation.

    R403.3.1.2 Attachment to heated structure.

    Where a frost-protected shallow foundation abuts a structure that has a monthly mean temperature maintained at a minimum of 64°F (18°C), horizontal insulation and vertical wall insulation shall not be required between the frost-protected shallow foundation and the adjoining structure. Where the frost-protected shallow foundation abuts the heated structure, the horizontal insulation and vertical wall insulation shall extend along the adjoining foundation in accordance with Figure R403.3(4) a distance of not less than Dimension A in Table R403.3(1).

    Exception: Where the frost-protected shallow foundation abuts the heated structure to form an inside corner, vertical insulation extending along the adjoining foundation is not required.

    R403.3.2 Protection of horizontal insulation below ground.

    Horizontal insulation placed less than 12 inches (305 mm) below the ground surface or that portion of horizontal insulation extending outward more than 24 inches (610 mm) from the foundation edge shall be protected against damage by use of a concrete slab or asphalt paving on the ground surface directly above the insulation or by cementitious board, plywood rated for below-ground use, or other approved materials placed below ground, directly above the top surface of the insulation.

    R403.3.3 Drainage.

    Final grade shall be sloped in accordance with Section R401.3. In other than Group I Soils, as detailed in Table R405.1, gravel or crushed stone beneath horizontal insulation below ground shall drain to daylight or into an approved sewer system.

    R403.3.4 Termite protection.

    The use of foam plastic in areas of “very heavy” termite infestation probability shall be in accordance with Section R318.4.

    R403.4 Footings for precast concrete foundations.

    Footings for precast concrete foundations shall comply with Section R403.4.

    TABLE R403.4

    MINIMUM DEPTH OF CRUSHED STONE FOOTINGSa (D), (inches)

    NUMBER OF STORIESUNIFORM WALL LOADLOAD-BEARING VALUE OF SOIL (psf)
    1500200030004000
    MH, CH, CL, MLSC, GC, SM, GM, SP, SWGP, GW
    Wall width (inches)Wall width (inches)Wall width (inches)Wall width (inches)
    681012681012681012681012
    Conventional light-frame construction
    1-story1100 plf6444644464446444
    2-story1800 plf8644644464446444
    3-story2900 plf161412101086664446444
    4-inch brick veneer over light-frame or 8-inch hollow concrete masonry
    1-story1500 plf6444644464446444
    2-story2700 plf14121081086464446444
    3-story4000 plf2222201816141210108646444
    8-inch solid or fully grouted masonry
    1-story2000 plf10864644464446444
    2-story3600 plf20181616141210886446444
    3-story5300 plf3230282622222018141210810864

    For SI: 1 inch = 25.4 mm, 1 plf = 14.6 N/m, 1 pound per square foot = 47.9 N/m2.

    1. a.Linear interpolation of stone depth between wall widths is permitted within each Load-Bearing Value of Soil (psf).

    FIGURE R403.4(1)

    BASEMENT OR CRAWL SPACE WITH PRECAST FOUNDATION WALL BEARING ON CRUSHED STONE

    FIGURE R403.4(2)

    BASEMENT OR CRAWL SPACE WITH PRECAST FOUNDATION WALL ON SPREAD FOOTING

    R403.4.1 Crushed stone footings.

    Clean crushed stone shall be free from organic, clayey or silty soils. Crushed stone shall be angular in nature and meet ASTM C 33, with the maximum size stone not to exceed 1/2 inch (12.7 mm) and the minimum stone size not to be smaller than 1/16 inch (1.6 mm). Crushed stone footings for precast foundations shall be installed in accordance with Figure R403.4(1) and Table R403.4. Crushed stone footings shall be consolidated using a vibratory plate in a maximum of 8-inch (203 mm) lifts. Crushed stone footings shall be limited to Seismic Design Categories A, B and C.

    R403.4.2 Concrete footings.

    Concrete footings shall be installed in accordance with Section R403.1 and Figure R403.4(2).

    SECTIONR404
    FOUNDATION AND RETAINING WALLS  

    R404.1 Concrete and masonry foundation walls.

    Concrete foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.3. Masonry foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.2.

    R404.1.1 Design required.

    Concrete or masonry foundation walls shall be designed in accordance with accepted engineering practice where either of the following conditions exists:

    1. 1.Walls are subject to hydrostatic pressure from ground water.

    2. 2.Walls supporting more than 48 inches (1219 mm) of unbalanced backfill that do not have permanent lateral support at the top or bottom.

    TABLE R404.1.1(1)

    PLAIN MASONRY FOUNDATION WALLSf

    MAXIMUM WALL HEIGHT (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTc (feet)PLAIN MASONRYa MINIMUM NOMINAL WALL THICKNESS (inches)
    Soil classesb
    GW, GP, SW and SPGM, GC, SM, SM-SC and MLSC, MH, ML-CL and inorganic CL
    546 solidd or 86 solidd or 86 solidd or 8
    56 solidd or 8810
    646 solidd or 86 solidd or 86 solidd or 8
    56 solidd or 8810
    681012
    746 solidd or 888
    56 solidd or 81010
    6101210 solidd
    71210 solidd12 solidd
    846 solidd or 86 solidd or 88
    56 solidd or 81012
    6101212 solidd
    71212 soliddFootnote e
    810 groutd12 groutdFootnote e
    946 groutd or 8 solidd or 126 groutd or 8 solidd8 groutd or 10 solidd
    56 groutd or 10 solidd8 groutd or 12 solidd8 groutd
    68 groutd or 12 solidd10 groutd10 groutd
    710 groutd10 groutd12 grout
    810 groutd12 groutFootnote e
    912 groutFootnote eFootnote e

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 Pa.

    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond. Ungrouted hollow masonry units are permitted except where otherwise indicated.

    2. b.Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.

    3. c.Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.

    4. d.Solid indicates solid masonry unit; grout indicates grouted hollow units.

    5. e.Wall construction shall be in accordance with either Table R404.1.1(2), Table R404.1.1(3), Table R404.1.1(4), or a design shall be provided.

    6. f.The use of this table shall be prohibited for soil classifications not shown.

    TABLE R404.1.1(2)

    8-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 5 INCHESa, c, f

    WALL HEIGHTHEIGHT OF UNBALANCED BACKFILLeMINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
    Soil classes and lateral soil loadd (psf per foot below grade)
    GW, GP, SW and SP soils 30GM, GC, SM, SM-SC and ML soils 45SC, ML-CL and inorganic CL soils 60
    6 feet 8 inches4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#4 at 48
    6 feet 8 inches#4 at 48#5 at 48#6 at 48
    7 feet 4 inches4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#4 at 48
    6 feet#4 at 48#5 at 48#5 at 48
    7 feet 4 inches#5 at 48#6 at 48#6 at 40
    8 feet4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#4 at 48
    6 feet#4 at 48#5 at 48#5 at 48
    7 feet#5 at 48#6 at 48#6 at 40
    8 feet#5 at 48#6 at 48#6 at 32
    8 feet 8 inches4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#5 at 48
    6 feet#4 at 48#5 at 48#6 at 48
    7 feet#5 at 48#6 at 48#6 at 40
    8 feet 8 inches#6 at 48#6 at 32#6 at 24
    9 feet 4 inches4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#5 at 48
    6 feet#4 at 48#5 at 48#6 at 48
    7 feet#5 at 48#6 at 48#6 at 40
    8 feet#6 at 48#6 at 40#6 at 24
    9 feet 4 inches#6 at 40#6 at 24#6 at 16
    10 feet4 feet (or less)#4 at 48#4 at 48#4 at 48
    5 feet#4 at 48#4 at 48#5 at 48
    6 feet#4 at 48#5 at 48#6 at 48
    7 feet#5 at 48#6 at 48#6 at 32
    8 feet#6 at 48#6 at 32#6 at 24
    9 feet#6 at 40#6 at 24#6 at 16
    10 feet#6 at 32#6 at 16#6 at 16

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond.

    2. b.Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 5 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.

    5. e.Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.

    6. f.The use of this table shall be prohibited for soil classifications not shown.

    TABLE R404.1.1(3)

    10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 6.75 INCHESa, c, f

    WALL HEIGHTHEIGHT OF UNBALANCED BACKFILLeMINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
    Soil classes and later soil loadd (psf per foot below grade)
    GW, GP, SW and SP soils 30GM, GC, SM, SM-SC and ML soils 45SC, ML-CL and inorganic CL soils 60
    6 feet 8 inches4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet 8 inches#4 at 56#5 at 56#5 at 56
    7 feet 4 inches4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet#4 at 56#4 at 56#5 at 56
    7 feet 4 inches#4 at 56#5 at 56#6 at 56
    8 feet4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet#4 at 56#4 at 56#5 at 56
    7 feet#4 at 56#5 at 56#6 at 56
    8 feet#5 at 56#6 at 56#6 at 48
    8 feet 8 inches4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet#4 at 56#4 at 56#5 at 56
    7 feet#4 at 56#5 at 56#6 at 56
    8 feet 8 inches#5 at 56#6 at 48#6 at 32
    9 feet 4 inches4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet#4 at 56#5 at 56#5 at 56
    7 feet#4 at 56#5 at 56#6 at 56
    8 feet#5 at 56#6 at 56#6 at 40
    9 feet 4 inches#6 at 56#6 at 40#6 at 24
    10 feet4 feet (or less)#4 at 56#4 at 56#4 at 56
    5 feet#4 at 56#4 at 56#4 at 56
    6 feet#4 at 56#5 at 56#5 at 56
    7 feet#5 at 56#6 at 56#6 at 48
    8 feet#5 at 56#6 at 48#6 at 40
    9 feet#6 at 56#6 at 40#6 at 24
    10 feet#6 at 48#6 at 32#6 at 24

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond.

    2. b.Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 6.75 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.

    5. e.Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground level. Where an interior concrete slab-on-grade is provided and is in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height from the exterior finish ground level to the top of the interior concrete slab is permitted.

    6. f.The use of this table shall be prohibited for soil classifications not shown.

    TABLE R404.1.1(4)

    12-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d ≥ 8.75 INCHESa, c, f

    WALL HEIGHTHEIGHT OF UNBALANCED BACKFILLeMINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES)b, c
    Soil classes and lateral soil loadd(psf per foot below grade)
    GW, GP, SW and SP soils 30GM, GC, SM, SM-SC and ML soils 45SC, ML-CL and inorganic CL soils 60
    6 feet 8 inches4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet 8 inches#4 at 72#4 at 72#5 at 72
    7 feet 4 inches4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet#4 at 72#4 at 72#5 at 72
    7 feet 4 inches#4 at 72#5 at 72#6 at 72
    8 feet4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet#4 at 72#4 at 72#5 at 72
    7 feet#4 at 72#5 at 72#6 at 72
    8 feet#5 at 72#6 at 72#6 at 64
    8 feet 8 inches4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet#4 at 72#4 at 72#5 at 72
    7 feet#4 at 72#5 at 72#6 at 72
    8 feet 8 inches#5 at 72#7 at 72#6 at 48
    9 feet 4 inches4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet#4 at 72#5 at 72#5 at 72
    7 feet#4 at 72#5 at 72#6 at 72
    8 feet#5 at 72#6 at 72#6 at 56
    9 feet 4 inches#6 at 72#6 at 48#6 at 40
    10 feet4 feet (or less)#4 at 72#4 at 72#4 at 72
    5 feet#4 at 72#4 at 72#4 at 72
    6 feet#4 at 72#5 at 72#5 at 72
    7 feet#4 at 72#6 at 72#6 at 72
    8 feet#5 at 72#6 at 72#6 at 48
    9 feet#6 at 72#6 at 56#6 at 40
    10 feet#6 at 64#6 at 40#6 at 32

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square foot per foot = 0.157 kPa/mm.

    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond.

    2. b.Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D0, D1 and D2.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance, d, from the face of the soil side of the wall to the center of vertical reinforcement shall be not less than 8.75 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System and design lateral soil loads are for moist conditions without hydrostatic pressure. Refer to Table R405.1.

    5. e.Unbalanced backfill height is the difference in height between the exterior finish ground level and the lower of the top of the concrete footing that supports the foundation wall or the interior finish ground levels. Where an interior concrete slab-on-grade is provided and in contact with the interior surface of the foundation wall, measurement of the unbalanced backfill height is permitted to be measured from the exterior finish ground level to the top of the interior concrete slab is permitted.

    6. f.The use of this table shall be prohibited for soil classifications not shown.

    R404.1.2 Design of masonry foundation walls.

    Masonry foundation walls shall be designed and constructed in accordance with the provisions of this section or in accordance with the provisions of TMS 402/ACI 530/ASCE 5. When TMS 402/ACI 530/ASCE 5 or the provisions of this section are used to design masonry foundation walls, project drawings, typical details and specifications are not required to bear the seal of the architect or engineer responsible for design, unless otherwise required by the state law of the jurisdiction having authority.

    TABLE R404.1.2(1)

    MINIMUM HORIZONTAL REINFORCEMENT FOR CONCRETE BASEMENT WALLSa, b

    MAXIMUM UNSUPPORTED HEIGHT OF BASEMENT WALL (feet)LOCATION OF HORIZONTAL REINFORCEMENT
    ≤ 8One No. 4 bar within 12 inches of the top of the wall story and one No. 4 bar near mid-height of the wall story.
    > 8One No. 4 bar within 12 inches of the top of the wall story and one No. 4 bar near third points in the wall story.

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa.

    1. a.Horizontal reinforcement requirements are for reinforcing bars with a minimum yield strength of 40,000 psi and concrete with a minimum concrete compressive strength of 2,500 psi.

    2. b.See Section R404.1.3.2 for minimum reinforcement required for foundation walls supporting above-grade concrete walls.

    TABLE R404.1.2(2)

    MINIMUM VERTICAL REINFORCEMENT FOR 6-INCH NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, g, h, i, j, k

    MAXIMUM UNSUPPORTED WALL HEIGHT (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTf (feet)MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
    Soil classesa and design lateral soil (psf per foot of depth)
    GW, GP, SW, SP 30GM, GC, SM, SM-SC and ML 45SC, ML-CL and inorganic CL 60
    84NRNRNR
    5NR6 @ 396 @ 48
    65 @ 396 @ 486 @ 35
    76 @ 486 @ 346 @ 25
    86 @ 396 @ 256 @ 18
    94NRNRNR
    5NR5 @ 376 @ 48
    65 @ 366 @ 446 @ 32
    76 @ 476 @ 306 @ 22
    86 @ 346 @ 226 @ 16
    96 @ 276 @ 17DR
    104NRNRNR
    5NR5 @ 356 @ 48
    66 @ 486 @ 416 @ 30
    76 @ 436 @ 286 @ 20
    86 @ 316 @ 20DR
    96 @ 246 @ 15DR
    106 @ 19DRDR

    For SI: 1 inch = 25.4 mm; 1 foot = 304.8 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

    NR = Not required.

    1. a.Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.

    2. b.Table values are based on reinforcing bars with a minimum yield strength of 60,000 psi concrete with a minimum specified compressive strength of 2,500 psi and vertical reinforcement being located at the centerline of the wall. See Section R404.1.3.3.7.2.

    3. c.Vertical reinforcement with a yield strength of less than 60,000 psi and/or bars of a different size than specified in the table are permitted in accordance with Section R404.1.3.3.7.6 and Table R404.1.2(9).

    4. d.Deflection criterion is L/240, where L is the height of the basement wall in inches.

    5. e.Interpolation is not permitted.

    6. f.Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.

    7. g.NR indicates no vertical wall reinforcement is required, except for 6-inch-nominal walls formed with stay-in-place forming systems in which case vertical reinforcement shall be No. 4@48 inches on center.

    8. h.See Section R404.1.3.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    9. i.See Table R608.3 for tolerance from nominal thickness permitted for flat walls.

    10. j.DR means design is required in accordance with the applicable building code, or where there is no code, in accordance with ACI 318.

    11. k.The use of this table shall be prohibited for soil classifications not shown.

    TABLE R404.1.2(3)

    MINIMUM VERTICAL REINFORCEMENT FOR 8-INCH (203 mm) NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, f, h, i, j

    MAXIMUM UNSUPPORTED WALL HEIGHT (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTg (feet)MINIMUM VERTICAL REINFORCEMENT-BAR SIZE AND SPACING (inches)
    Soil classesa and design lateral soil (psf per foot of depth)
    GW, GP, SW, SP 30GM, GC, SM, SM-SC and ML 45SC, ML-CL and inorganic CL 60
    84NRNRNR
    5NRNRNR
    6NRNR6 @ 37
    7NR6 @ 366 @ 35
    86 @ 416 @ 356 @ 26
    94NRNRNR
    5NRNRNR
    6NRNR6 @ 35