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  • CHAPTER4
    FOUNDATIONS

    SECTIONR401
    GENERAL

    R401.1Application.

    The provisions of this chapter shall control the design and construction of the foundation and foundation spaces for all buildings. Wood foundations shall be designed and installed in accordance with AF&PA 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.When 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.

    R401.2Requirements.

    Foundation construction shall be capable of accommodating all loads according to 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.

    R401.3Drainage.

    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.

    R401.4Soil 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.

    R401.4.1Geotechnical 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 clay, silty clay, clayey silt, silt and sandy silt (CL, ML, MH and CH)1,500b

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

    1. a.When 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.

    R401.4.2Compressible or shifting soil.

    Instead of a complete geotechnical evaluation, when top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to assure 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

    R402.1Wood foundations.

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

    R402.1.1Fasteners.

    Fasteners used below grade to attach plywood to the exterior side of exterior basement or crawlspace 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.

    R402.1.2Wood 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.

    R402.2Concrete.

    Concrete shall have a minimum specified compressive strength of fc, 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 4.2.3 of ACI 318. Materials used to produce concrete and testing thereof shall comply with the applicable standards listed in Chapter 3 of ACI 318 or ACI 332.

    TABLE R402.2

    MINIMUM SPECIFIED COMPRESSIVE STRENGTH OF CONCRETE

    TYPE OR LOCATION OF CONCRETE CONSTRUCTIONMINIMUM SPECIFIED COMPRESSIVE STRENGTHa (f′c)
    Weathering Potentialb
    NegligibleModerateSevere
    Footingsg5,0005,0005,000
    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 may be 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.

    7. g.Compressive strength (f′c) of 2,500 psi, with an approved admixture that provides a water and vapor resistance at least equivalent to 5,000 psi concrete.

    R402.3Precast 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 installation instructions.

    R402.3.1Precast 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.

    SECTIONR403
    FOOTINGS

    R403.1General.

    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

    MINIMUM WIDTH OF CONCRETE, PRECAST OR MASONRY FOOTINGS (inches)a

     LOAD-BEARING VALUE OF SOIL (psf)
    1,5002,0003,000≥ 4,000
    Conventional light-frame construction
    1-story12121212
    2-story15121212
    3-story23171212
    4-inch brick veneer over light frame or 8-inch hollow concrete masonry
    1-story12121212
    2-story21161212
    3-story32241612
    8-inch solid or fully grouted masonry
    1-story16121212
    2-story29211412
    3-story42322116

    For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa.

    1. a.Where minimum footing width is 12 inches, use of a single wythe of solid or fully grouted 12-inch nominal concrete masonry units is permitted.

    For SI: 1 inch = 25.4 mm.

    FIGURE R403.1(1)

    CONCRETE AND MASONRY FOUNDATION DETAILS

    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

    R403.1.1Minimum size.

    Minimum sizes for concrete and masonry footings shall be as set forth in Table R403.1 and Figure R403.1(1). The footing width, W, shall be based on the load-bearing value of the soil in accordance with Table R401.4.1. Spread footings shall be at least 6 inches (152 mm) in thickness, T. Footing projections, P, shall be at least 2 inches (51 mm) and shall not exceed the thickness of the footing. 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).

    R403.1.2Continuous footing in Seismic Design Categories D0, D1 and D2.

    The braced wall panels at exterior walls of buildings located in Seismic Design Categories D0, D1 and D2 shall be supported by continuous footings. All required interior braced wall panels in buildings with plan dimensions greater than 50 feet (15 240 mm) shall also be supported by continuous footings.

    R403.1.3Seismic reinforcing.

    Concrete footings located in Seismic Design Categories D0, D1 and D2, as established in Table R301.2(1), shall have minimum reinforcement. Bottom reinforcement shall be located a minimum of 3 inches (76 mm) clear from the bottom of the footing.

    In Seismic Design Categories D0, D1 and D2 where a construction joint is created between a concrete footing and a stem wall, a minimum of one No. 4 bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall extend to 3 inches (76 mm) clear of the bottom of the footing, have a standard hook and extend a minimum of 14 inches (357 mm) into the stem wall.

    In Seismic Design Categories D0, D1 and D2 where a grouted masonry stem wall is supported on a concrete footing and stem wall, a minimum of one No. 4 bar shall be installed at not more than 4 feet (1219 mm) on center. The vertical bar shall extend to 3 inches (76 mm) clear of the bottom of the footing and have a standard hook.

    In Seismic Design Categories D0, D1 and D2 masonry stem walls without solid grout and vertical reinforcing are not permitted.

    Exception: In detached one- and two-family dwellings which are three stories or less in height and constructed with stud bearing walls, isolated plain concrete footings, supporting columns or pedestals are permitted.

    R403.1.3.1Foundations with stemwalls.

    Foundations with stem walls shall have installed a minimum of one No. 4 bar within 12 inches (305 mm) of the top of the wall and one No. 4 bar located 3 inches (76 mm) to 4 inches (102 mm) from the bottom of the footing.

    R403.1.3.2Slabs-on-ground with turned-down footings.

    Slabs on ground with turned down footings shall have a minimum of one No. 4 bar at the top and the bottom of the footing.

    Exception: For slabs-on-ground cast monolithically with the footing, locating one No. 5 bar or two No. 4 bars in the middle third of the footing depth shall be permitted as an alternative to placement at the footing top and bottom.

    Where the slab is not cast monolithically with the footing, No. 3 or larger vertical dowels with standard hooks on each end shall be provided in accordance with Figure R403.1.3.2. Standard hooks shall comply with Section R611.5.4.5.

    For SI: 1 inch = 25.4 mm.

    FIGURE R403.1.3.2

    DOWELS FOR SLABS-ON-GROUND WITH TURNED-DOWN FOOTINGS

    R403.1.4Minimum depth.

    All exterior footings shall be placed at least 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.

    R403.1.4.1Frost protection.

    Footings shall not bear on frozen soil. Foundation walls, piers, and other permanent supports of buildings and structures not otherwise protected from frost shall be protected by one or more of the following methods:

    1. 1.Extended below the frost line specified in Table R301.2(1);

    2. 2.Constructing in accordance with Section R403.3;

    3. 3.Constructing in accordance with ASCE 32;

    4. 4.Erected on solid rock; or

    5. 5.Constructing in accordance with Minnesota Rules, Chapter 1303.

    Exception: Decks not supported by a dwelling need not be provided with footings that extend below the frost line.

    R403.1.4.2Seismic conditions.

    In Seismic Design Categories D0, D1 and D2, interior footings supporting bearing or bracing walls 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.

    R403.1.5Slope.

    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 ten units horizontal (10-percent slope).

    R403.1.6Foundation anchorage.

    Sill plates and walls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.

    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 anchor bolts spaced a maximum of 6 feet (1829 mm) on center. Bolts shall be at least 1/2 inch (12.7 mm) in diameter and shall extend a minimum of 7 inches (178 mm) into concrete or grouted cells of concrete masonry units. A nut and washer shall be tightened on each 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 7 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. Cold-formed steel framing systems shall be fastened to the wood sill plates or anchored directly to the foundation as required in Section R505.3.1 or R603.1.1. When vertical reinforcing is required by other sections of this code, the foundation anchor bolts shall align with the reinforcing. All anchor bolts installed in masonry shall be grouted in place with at least 1 inch (25 mm) of grout between the bolt and the masonry.

    Exceptions:

    1. 1.Foundation anchor straps spaced as required to provide equivalent anchorage to 1/2-inch diameter (12.7 mm) anchor bolts. When vertical reinforcing is required by other sections of this code, the foundation anchor straps shall align with the reinforcing.

    2. 2.Walls 24 inches (609.6 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 according to Figure R602.10.5 at corners.

    3. 3.Walls 12 inches (304.8 mm) total length or shorter connecting offset braced wall panels shall be permitted to be connected to the foundation without anchor bolts. The wall shall be attached to adjacent braced wall panels according to Figure R602.10.5 at corners.

    R403.1.6.1Foundation 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).

    R403.1.7Footings 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.

    R403.1.7.1Building 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

    R403.1.7.2Footing 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.

    R403.1.7.3Foundation 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.

    R403.1.7.4Alternate setback 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.

    R403.1.8Foundations 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.

    R403.1.8.1Expansive 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.

    R403.2Footings 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).

    R403.3Frost-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 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. Date 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
    UtahAll counties not listedBox Elder, Morgan, WeberGarfield, Salt Lake, SummitCarbon, Daggett, Duchesne, Rich, Sanpete, Uintah, Wasatch
    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

    R403.3.1Foundations adjoining frost-protected shallow foundations.

    Foundations that adjoin frost-protected shallow foundations shall be protected from frost in accordance with Section R403.1.4.

    R403.3.1.1Attachment 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 either be 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.

    R403.3.1.2Attachment 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.

    R403.3.2Protection 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.

    R403.3.3Drainage.

    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.

    R403.3.4Termite damage.

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

    R403.4Footings for precast concrete foundations.

    Footings for precast concrete foundations shall comply with Section R403.4.

    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

    TABLE R403.4

    MINIMUM DEPTH OF CRUSHED STONE FOOTINGS (D), (inches)

     LOAD-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 pound per square inch = 6.89 pounds per linear foot, 1 plf = 2.44 N/m, 1 pounds per square foot = 47.9 N/m2.

    R403.4.1Crushed 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 lifts. Crushed stone footings shall be limited to Seismic Design Categories A, B and C.

    R403.4.2Concrete footings.

    Concrete footings shall be installed in accordance with Section R403.1 and Figure R403.4(2).

    SECTIONR404
    FOUNDATION AND RETAINING WALLS

    R404.1Concrete and masonry foundation walls.

    Concrete foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.2. Masonry foundation walls shall be selected and constructed in accordance with the provisions of Section R404.1.1. Concrete and masonry foundation walls shall be laterally supported at the top and bottom. Foundation walls that meet all of the following shall be considered laterally supported:

    1. 1.Full basement floor shall be 3.5 inches (89 mm) thick concrete slab poured tight against the bottom of the foundation wall.

    2. 2.Floor joists and blocking shall be connected to the sill plate at the top of wall with an approved connector with listed capacity meeting the top of wall reaction in Table R404.1(1). Maximum spacing of floor joists shall be 24 inches (610 mm) on center. Spacing of blocking shall be in accordance with Table R404.1(1).

    3. 3.Bolt spacing for the sill plate shall be no greater than the requirements in Table R404.1(1).

    4. 4.The floor shall be blocked perpendicular to the floor joists. Blocking shall be full depth within three joist spaces of the foundation wall. Floor sheathing shall be fastened to blocking in accordance with Table R602.3(1).

    5. 5.Where foundation walls support unbalanced load on opposite sides of the building, such as a daylight basement, the rim board shall be attached to the sill with a 20-gage metal angle clip at 24 inches (610 mm) on center, with five 8d nails per leg, or an approved connector supplying 230 pounds per lineal foot capacity.

    Exception: Cantilevered concrete and masonry foundation walls that do not have permanent lateral support at the top shall be constructed according to Table R404.1.1(5), Table R404.1.1(6), or Table R404.1.1(7).

    TABLE R404.1(1)

    MAXIMUM ANCHOR BOLT AND BLOCKING SPACING FOR SUPPORTED FOUNDATION WALL

    MAX. WALL HEIGHTMAX. UNBALANCED BACKFILL HEIGHTSOIL CLASSESSOIL LOAD (pcf/ft)TOP OF WALL REACTION (plf)b1/2" DIAMETER ANCHOR BOLT SPACING (inches)aSPACING OF BLOCKING PERPENDICULAR TO FLOOR JOISTS (inches)
    8′-0"7′-4"GW, GP, SW, & SP302507260
    GM, GC, SM-SC, & ML453707240
    SC, MH, ML-CL, & I-CL604904830
    9′-0"8′-4"GW, GP, SW, & SP303207248
    GM, GC, SM-SC, & ML454804832
    SC, MH, ML-CL, & I-CL606404024

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

    1. a.Sill plate shall be 2 x 6 minimum. Anchor bolt shall be minimum 0.5" diameter cast-in-place with 7" embed. Anchor bolt shall have a 2" diameter by 0.125" thick washer tightened and countersunk 0.25" into the top of the sill plate.

    2. b.Minimum load to be used for sizing of accepted anchors or fasteners if bolts are not used.

    R404.1.1Design 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 or NCMA TR68-A. When TMS 402/ACI 530/ASCE 5, NCMA TR68-A 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 R404.1.1(1)

    PLAIN MASONRY FOUNDATION WALLS

    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 solidd12 soliddFootnote e
    946 solidd or 86 solidd or 88
    581012
    6101212 solidd
    71212 soliddFootnote e
    812 soliddFootnote eFootnote e
    9Footnote eFootnote 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 grouted hollow units or solid masonry 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.

    TABLE R404.1.1(2)

    8-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d > 5 INCHESa, c

    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) 5 feet 6 feet 8 inches#4 at 48 #4 at 48 #4 at 48#4 at 48 #4 at 48 #5 at 48#4 at 48 #4 at 48 #6 at 48
    7 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 4 inches#4 at 48 #4 at 48 #4 at 48 #5 at 48#4 at 48 #4 at 48 #5 at 48 #6 at 48#4 at 48 #4 at 48 #5 at 48 #6 at 40
    8 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet#4 at 48 #4 at 48 #4 at 48 #5 at 48 #5 at 48#4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 48#4 at 48 #4 at 48 #5 at 48 #6 at 40 #6 at 32
    8 feet 8 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 8 inches#4 at 48 #4 at 48 #4 at 48 #5 at 48 #6 at 48#4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 32#4 at 48 #5 at 48 #6 at 48 #6 at 40 #6 at 24
    9 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 4 inches#4 at 48 #4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 40#4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 40 #6 at 24#4 at 48 #5 at 48 #6 at 48 #6 at 40 #6 at 24 #6 at 16
    10 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 10 feet#4 at 48 #4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 40 #6 at 32#4 at 48 #4 at 48 #5 at 48 #6 at 48 #6 at 32 #6 at 24 #6 at 16#4 at 48 #5 at 48 #6 at 48 #6 at 32 #6 at 24 #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.

    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 at least 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.

    TABLE R404.1.1(3)

    10-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d > 6.75 INCHESa, c

    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) 5 feet 6 feet 8 inches#4 at 56 #4 at 56 #4 at 56#4 at 56 #4 at 56 #5 at 56#4 at 56 #4 at 56 #5 at 56
    7 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 4 inches#4 at 56 #4 at 56 #4 at 56 #4 at 56#4 at 56 #4 at 56 #4 at 56 #5 at 56#4 at 56 #4 at 56 #5 at 56 #6 at 56
    8 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet#4 at 56 #4 at 56 #4 at 56 #4 at 56 #5 at 56#4 at 56 #4 at 56 #4 at 56 #5 at 56 #6 at 56#4 at 56 #4 at 56 #5 at 56 #6 at 56 #6 at 48
    8 feet 8 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 8 inches#4 at 56 #4 at 56 #4 at 56 #4 at 56 #5 at 56#4 at 56 #4 at 56 #4 at 56 #5 at 56 #6 at 48#4 at 56 #4 at 56 #5 at 56 #6 at 56 #6 at 32
    9 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 4 inches#4 at 56 #4 at 56 #4 at 56 #4 at 56 #5 at 56 #6 at 56#4 at 56 #4 at 56 #5 at 56 #5 at 56 #6 at 56 #6 at 40#4 at 56 #4 at 56 #5 at 56 #6 at 56 #6 at 40 #6 at 24
    10 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 10 feet#4 at 56 #4 at 56 #4 at 56 #5 at 56 #5 at 56 #6 at 56 #6 at 48#4 at 56 #4 at 56 #5 at 56 #6 at 56 #6 at 48 #6 at 40 #6 at 32#4 at 56 #4 at 56 #5 at 56 #6 at 48 #6 at 40 #6 at 24 #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.

    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 at least 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.

    TABLE R404.1.1(4)

    12-INCH MASONRY FOUNDATION WALLS WITH REINFORCING WHERE d > 8.75 INCHESa, c

    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) 5 feet 6 feet 8 inches#4 at 72 #4 at 72 #4 at 72#4 at 72 #4 at 72 #4 at 72#4 at 72 #4 at 72 #5 at 72
    7 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 4 inches#4 at 72 #4 at 72 #4 at 72 #4 at 72#4 at 72 #4 at 72 #4 at 72 #5 at 72#4 at 72 #4 at 72 #5 at 72 #6 at 72
    8 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet#4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72#4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72#4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 64
    8 feet 8 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 8 inches#4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72#4 at 72 #4 at 72 #4 at 72 #5 at 72 #7 at 72#4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 48
    9 feet 4 inches4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 4 inches#4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72#4 at 72 #4 at 72 #5 at 72 #5 at 72 #6 at 72 #6 at 48#4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 56 #6 at 40
    10 feet4 feet (or less) 5 feet 6 feet 7 feet 8 feet 9 feet 10 feet#4 at 72 #4 at 72 #4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 64#4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 72 #6 at 56 #6 at 40#4 at 72 #4 at 72 #5 at 72 #6 at 72 #6 at 48 #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.

    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 at least 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.

    TABLE R404.1.1(5)

    CANTILEVERED CONCRETE AND MASONRY FOUNDATION WALLS

    MAXIMUM WALL HEIGHTj (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTe (feet)MINIMUM VERTICAL REINFORCEMENT SIZE AND SPACING FOR 8-INCH NOMINAL WALL THICKNESSa,b,c,e,f,i,k
    Soil Classesd
    GW, GP, SW, and SPGM, GC, SM, SM-SC, and MLSC, MH, ML-CL, and inorganic CL
    43None requiredNone requiredNone required
    4None requiredNone requiredNo. 4 @ 72 in. o.c.
    53None requiredNone requiredNone required
    4No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.hNo. 4 @ 40 in. o.c.g
    5No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.hNo. 4 @ 40 in. o.c.g
    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond. Minimum unit compressive strength is 1,900 psi.

    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.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance from the face of the soil side of the wall to the center of vertical reinforcement shall be no greater than 2.5 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.

    5. e.Interior concrete floor slab-on-grade shall be placed tight to the wall. The exterior grade level shall be 6 inches minimum below the top of wall. Maximum height from top of slab-on-grade to bottom of floor joists is 10 feet, 0 inches. Unbalanced backfill height is the difference in height of the exterior finish ground levels and the top of the interior concrete slab-on-grade.

    6. f.Minimum footing size of 20 inches by 8 inches shall be placed on soil with a bearing capacity of 2,000 psf. Minimum concrete compressive strength of footing shall be 3,000 psi.

    7. g.Provide propped cantilever wall: top of footing shall be 16 inches below the bottom of the concrete floor slab minimum.

    8. h.Provide #5 Grade 60 dowels, 1 foot, 6 inches long, to connect footing to wall. Embed dowel 5 inches into footing. Place dowels in center of wall thickness spaced at 32 inches on center maximum. No dowels are required where length of the foundation wall between perpendicular walls is two times the foundation wall height or less.

    9. i.This table is applicable where the length of the foundation wall between perpendicular walls is 35 feet or less, or where the length of the foundation laterally supported on only one end by a perpendicular wall is 17 feet or less.

    10. j.Maximum wall height is measured from top of the foundation wall to the bottom of the interior concrete slab-on-grade.

    11. k.Install foundation anchorage per Section R403.1.6.

    TABLE R404.1.1(6)

    CANTILEVERED CONCRETE AND MASONRY FOUNDATION WALLS

    MAXIMUM WALL HEIGHTj (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTe (feet)MINIMUM VERTICAL REINFORCEMENT SIZE AND SPACING FOR 10-INCH NOMINAL WALL THICKNESSa,b,c,e,f,i,k
    Soil Classesd
    GW, GP, SW, and SPGM, GC, SM, SM-SC, and MLSC, MH, ML-CL, and inorganic CL
    43None requiredNone requiredNone required
    4None requiredNone requiredNone required
    53None requiredNone requiredNone required
    4None requiredNo. 4 @ 72 in. o.c.No. 4 @ 64 in. o.c.g
    5No. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.g
    63None requiredNo. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.
    4No. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.No. 4 @ 64 in. o.c.h
    5No. 4 @ 64 in. o.c.hNo. 4 @ 40 in. o.c.g,hNo. 5 @ 48 in. o.c.g,h
    6No. 4 @ 64 in. o.c.hNo. 4 @ 40 in. o.c.g,hNo. 5 @ 48 in. o.c.g,h
    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond. Minimum unit compressive strength is 1,900 psi.

    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.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance from the face of the soil side of the wall to the center of vertical reinforcement shall be no greater than 2.5 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.

    5. e.Interior concrete slab-on-grade shall be placed tight to the wall. The exterior grade level shall be 6 inches minimum below the top of wall. Maximum height from top of slab-on-grade to bottom of floor joists is 10 feet, 0 inches. Unbalanced backfill height is the difference in height of the exterior finish ground levels and the top of the interior concrete slab-on-grade.

    6. f.Minimum footing size of 20 inches by 8 inches shall be placed on soil with a bearing capacity of 2,000 psf. Minimum concrete compressive strength of footing shall be 3,000 psi.

    7. g.Provide propped cantilever wall: top of footing shall be 16 inches below the bottom of the concrete floor slab minimum.

    8. h.Provide #5 Grade 60 dowels, 1 foot, 6 inches long, to connect footing to wall. Embed dowel 5 inches into footing. Place dowels in center of wall thickness spaced at 32 inches on center maximum. No dowels are required where length of the foundation wall between perpendicular walls is two times the foundation wall height or less.

    9. i.This table is applicable where the length of the foundation wall between perpendicular walls is 35 feet or less, or where the length of the foundation laterally supported on only one end by a perpendicular wall is 17 feet or less.

    10. j.Maximum wall height is measured from top of the foundation wall to the bottom of the interior concrete slab-on-grade.

    11. k.Install foundation anchorage per Section R403.1.6.

    TABLE R404.1.1(7)

    CANTILEVERED CONCRETE AND MASONRY FOUNDATION WALLS

    MAXIMUM WALL HEIGHTj (feet)MAXIMUM UNBALANCED BACKFILL HEIGHTe (feet)MINIMUM VERTICAL REINFORCEMENT SIZE AND SPACING FOR 12-INCH NOMINAL WALL THICKNESSa,b,c,e,f,i,k
    Soil Classesd
    GW, GP, SW, and SPGM, GC, SM, SM-SC, and MLSC, MH, ML-CL, and inorganic CL
    43None requiredNone requiredNone required
    4None requiredNone requiredNone required
    53None requiredNone requiredNone required
    4None requiredNone requiredNo. 4 @ 72 in. o.c.
    5No. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.
    63None requiredNone requiredNone required
    4None requiredNone requiredNo. 4 @ 72 in. o.c.
    5No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.hNo. 4 @ 40 in. o.c.g
    6No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.gNo. 4 @ 32 in. o.c.g,h
    73None requiredNone requiredNone required
    4None requiredNo. 4 @ 72 in. o.c.No. 4 @ 72 in. o.c.
    5No. 4 @ 72 in. o.c.No. 4 @ 56 in. o.c.hNo. 4 @ 40 in. o.c.g
    6No. 4 @ 48 in. o.c.hNo. 5 @ 48 in. o.c.g,hNo. 6 @ 48 in. o.c.g,h
    7No. 4 @ 48 in. o.c.hNo. 5 @ 40 in. o.c.g,hNo. 6 @ 48 in. o.c.g,h
    1. a.Mortar shall be Type M or S and masonry shall be laid in running bond. Minimum unit compressive strength is 1,900 psi.

    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.

    3. c.Vertical reinforcement shall be Grade 60 minimum. The distance from the face of the soil side of the wall to the center of vertical reinforcement shall be no greater than 3 inches.

    4. d.Soil classes are in accordance with the Unified Soil Classification System. Refer to Table R405.1.

    5. e.Interior concrete slab-on-grade shall be placed tight to the wall. The exterior grade level shall be 6 inches minimum below the top of wall. Maximum height from top of slab-on-grade to bottom of floor joists is 10 feet, 0 inches. Unbalanced backfill height is the difference in height of the exterior finish ground levels and the top of the interior concrete slab-on-grade.

    6. f.Minimum footing size of 20 inches by 8 inches shall be placed on soil with a bearing capacity of 2,000 psf. Minimum concrete compressive strength of footing shall be 3,000 psi.

    7. g.Provide propped cantilever wall: top of footing shall be 16 inches below the bottom of the concrete floor slab minimum.

    8. h.Provide #5 Grade 60 dowels, 1 foot, 6 inches long, to connect footing to wall. Embed dowel 5 inches into footing. Place dowels in center of wall thickness spaced at 32 inches on center maximum. No dowels are required where length of the foundation wall between perpendicular walls is two times the foundation wall height or less.

    9. i.This table is applicable where the length of the foundation wall between perpendicular walls is 35 feet or less, or where the length of the foundation laterally supported on only one end by a perpendicular wall is 17 feet or less.

    10. j.Maximum wall height is measured from top of the foundation wall to the bottom of the interior concrete slab-on-grade.

    11. k.Install foundation anchorage per Section R403.1.6.

    R404.1.1.1Masonry foundation walls.

    Concrete masonry and clay masonry foundation walls shall be constructed as set forth in Table R404.1.1(1), R404.1.1(2), R404.1.1(3) or R404.1.1(4) and shall also comply with applicable provisions of Sections R606, R607 and R608. In buildings assigned to Seismic Design Categories D0, D1 and D2, concrete masonry and clay masonry foundation walls shall also comply with Section R404.1.4.1. Rubble stone masonry foundation walls shall be constructed in accordance with Sections R404.1.8 and R607.2.2. Rubble stone masonry walls shall not be used in Seismic Design Categories D0, D1 and D2.

    R404.1.2Concrete foundation walls.

    Concrete foundation walls that support light-frame walls shall be designed and constructed in accordance with the provisions of this section, ACI 318, ACI 332 or PCA 100. Concrete foundation walls that support above-grade concrete walls that are within the applicability limits of Section R611.2 shall be designed and constructed in accordance with the provisions of this section, ACI 318, ACI 332 or PCA 100. Concrete foundation walls that support above-grade concrete walls that are not within the applicability limits of Section R611.2 shall be designed and constructed in accordance with the provisions of ACI 318, ACI 332 or PCA 100. When ACI 318, ACI 332, PCA 100 or the provisions of this section are used to design concrete 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 2,500 psi.

    2. b.See Section R404.1.2.2 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

    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 foot = 304.8 mm; 1 inch = 25.4 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 R404.1.2.3.7.2.

    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 R404.1.2.3.7.6 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 R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    9. i.See Table R611.3 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.

    TABLE R404.1.2(3)

    MINIMUM VERTICAL REINFORCEMENT FOR 8-INCH (203 mm) NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, f, h, i

    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
    7NR6 @ 356 @ 32
    86 @ 366 @ 326 @ 23
    96 @ 356 @ 256 @ 18
    104NRNRNR
    5NRNRNR
    6NRNR6 @ 35
    7NR6 @ 356 @ 29
    86 @ 356 @ 296 @ 21
    96 @ 346 @ 226 @ 16
    106 @ 276 @ 176 @ 13

    For SI: 1 foot = 304.8 mm; 1 inch = 25.4 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 R404.1.2.3.7.2.

    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 R404.1.2.3.7.6 and Table R404.1.2(9).

    4. d.NR indicates no vertical reinforcement is required.

    5. e.Deflection criterion is L/240, where L is the height of the basement wall in inches.

    6. f.Interpolation is not permitted.

    7. g.Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.

    8. h.See Section R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    9. i.See Table R611.3 for tolerance from nominal thickness permitted for flat walls.

    TABLE R404.1.2(4)

    MINIMUM VERTICAL REINFORCEMENT FOR 10-INCH NOMINAL FLAT CONCRETE BASEMENT WALLSb, c, d, e, f, h, i

    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
    6NRNRNR
    7NRNRNR
    86 @ 486 @ 356 @ 28
    94NRNRNR
    5NRNRNR
    6NRNRNR
    7NRNR6 @ 31
    8NR6 @ 316 @ 28
    96 @ 376 @ 286 @ 24
    104NRNRNR
    5NRNRNR
    6NRNRNR
    7NRNR6 @ 28
    8NR6 @ 286 @ 28
    96 @ 336 @ 286 @ 21
    106 @ 286 @ 236 @ 17

    For SI: 1 foot = 304.8 mm; 1 inch = 25.4 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 R404.1.2.3.7.2.

    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 R404.1.2.3.7.6 and Table R404.1.2(9).

    4. d.NR indicates no vertical reinforcement is required.

    5. e.Deflection criterion is L/240, where L is the height of the basement wall in inches.

    6. f.Interpolation is not permitted.

    7. g.Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.

    8. h.See Section R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    9. i.See Table R611.3 for tolerance from nominal thickness permitted for flat walls.

    TABLE R404.1.2(5)

    MINIMUM VERTICAL WALL REINFORCEMENT FOR 6-INCH WAFFLE-GRID BASEMENT WALLSb, c, d, e, g, h, i

    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
    844 @ 484 @ 466 @ 39
    54 @ 455 @ 466 @ 47
    65 @ 456 @ 40DR
    76 @ 44DRDR
    86 @ 32DRDR
    944 @ 484 @ 464 @ 37
    54 @ 425 @ 436 @ 44
    65 @ 416 @ 37DR
    76 @ 39DRDR
    > 8DRiDRDR
    1044 @ 484 @ 464 @ 35
    54 @ 405 @ 406 @ 41
    65 @ 386 @ 34DR
    76 @ 36DRDR
    > 8DRDRDR

    For SI: 1 foot = 304.8 mm; 1 inch = 25.4 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

    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 R404.1.2.3.7.2.

    3. c.Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (i.e., 12, 24, 36 and 48) that is less than or equal to the tabulated spacing. 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 R404.1.2.3.7.6 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.See Section R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    8. h.See Table R611.3 for thicknesses and dimensions of waffle-grid walls.

    9. i.DR means design is required in accordance with the applicable building code, or where there is no code, in accordance with ACI 318.

    TABLE R404.1.2(6)

    MINIMUM VERTICAL REINFORCEMENT FOR 8-INCH WAFFLE-GRID 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
    5NR5 @ 485 @ 46
    65 @ 485 @ 436 @ 45
    75 @ 466 @ 436 @ 31
    86 @ 486 @ 326 @ 23
    94NRNRNR
    5NR5 @ 475 @ 46
    65 @ 465 @ 396 @ 41
    75 @ 426 @ 386 @ 28
    86 @ 446 @ 286 @ 20
    96 @ 346 @ 21DR
    104NRNRNR
    5NR5 @ 465 @ 44
    65 @ 465 @ 376 @ 38
    75 @ 386 @ 356 @ 25
    86 @ 396 @ 25DR
    96 @ 30DRDR
    106 @ 24DRDR

    For SI: 1 foot = 304.8 mm; 1 inch = 25.4 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 R404.1.2.3.7.2.

    3. c.Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 (420 MPa) and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (i.e., 12, 24, 36 and 48) that is less than or equal to the tabulated spacing. 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 R404.1.2.3.7.6 and Table R404.1.2(9).

    4. d.NR indicates no vertical reinforcement is required.

    5. e.Deflection criterion is L/240, where L is the height of the basement wall in inches.

    6. f.Interpolation shall not be permitted.

    7. g.Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.

    8. h.See Section R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    9. i.See Table R611.3 for thicknesses and dimensions of waffle-grid 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.

    TABLE R404.1.2(7)

    MINIMUM VERTICAL REINFORCEMENT FOR 6-INCH (152 mm) SCREEN-GRID BASEMENT WALLSb, c, d, e, g, h, i

    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
    844 @ 484 @ 485 @ 43
    54 @ 485 @ 485 @ 37
    65 @ 486 @ 456 @ 32
    76 @ 48DRDR
    86 @ 36DRDR
    944 @ 484 @ 484 @ 41
    54 @ 485 @ 486 @ 48
    65 @ 456 @ 41DR
    76 @ 43DRDR
    > 8DRDRDR
    1044 @ 484 @ 484 @ 39
    54 @ 445 @ 446 @ 46
    65 @ 426 @ 38DR
    76 @ 40DRDR
    > 8DRDRDR

    For SI: 1 foot = 304.8 mm; 1 inch = 25.4 mm; 1 pound per square foot per foot = 0.1571 kPa2/m, 1 pound per square inch = 6.895 kPa.

    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 R404.1.2.3.7.2.

    3. c.Maximum spacings shown are the values calculated for the specified bar size. Where the bar used is Grade 60 and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (i.e., 12, 24, 36 and 48) that is less than or equal to the tabulated spacing. 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 R404.1.2.3.7.6 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.See Sections R404.1.2.2 for minimum reinforcement required for basement walls supporting above-grade concrete walls.

    8. h.See Table R611.3 for thicknesses and dimensions of screen-grid walls.

    9. i.DR means design is required in accordance with the applicable building code, or where there is no code, in accordance with ACI 318.

    TABLE R404.1.2(8)

    MINIMUM VERTICAL REINFORCEMENT FOR 6-, 8-, 10-INCH AND 12-INCH NOMINAL FLAT BASEMENT WALLSb, c, d, e, f, h, i, k, n

    MAXIMUM 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
    Minimum nominal wall thickness (inches)
    681012681012681012
    54NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNRNRNRNRNRNRNRNRNR
    64NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNRNRNRlNRNR4 @ 35NRlNRNR
    6NRNRNRNR5 @ 48NRNRNR5 @ 36NRNRNR
    74NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNRNRNRNRNR5 @ 47NRNRNR
    6NRNRNRNR5 @ 42NRNRNR6 @ 435 @ 48NRlNR
    75 @ 46NRNRNR6 @ 425 @ 46NRlNR6 @ 346 @ 48NRNR
    84NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNR4 @ 38NRlNRNR5 @ 43NRNRNR
    64 @ 37NRlNRNR5 @ 37NRNRNR6 @ 375 @ 43NRlNR
    75 @ 40NRNRNR6 @ 375 @ 41NRlNR6 @ 346 @ 43NRNR
    86 @ 435 @ 47NRlNR6 @ 346 @ 43NRNR6 @ 276 @ 326 @ 44NR
    94NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNR4 @ 35NRlNRNR5 @ 40NRNRNR
    64 @ 34NRlNRNR6 @ 48NRNRNR6 @ 366 @ 39NRlNR
    75 @ 36NRNRNR6 @ 345 @ 37NRNR6 @ 336 @ 385 @ 37NRl
    86 @ 385 @ 41NRlNR6 @ 336 @ 385 @ 37NRl6 @ 246 @ 296 @ 394 @ 48m
    96 @ 346 @ 46NRNR6 @ 266 @ 306 @ 41NR6 @ 196 @ 236 @ 306 @ 39
    104NRNRNRNRNRNRNRNRNRNRNRNR
    5NRNRNRNR4 @ 33NRlNRNR5 @ 38NRNRNR
    65 @ 48NRlNRNR6 @ 45NRNRNR6 @ 345 @ 37NRNR
    76 @ 47NRNRNR6 @ 346 @ 48NRNR6 @ 306 @ 356 @ 48NRl
    86 @ 345 @ 38NRNR6 @ 306 @ 346 @ 47NRl6 @ 226 @ 266 @ 356 @ 45m
    96 @ 346 @ 414 @ 48NRl6 @ 236 @ 276 @ 354 @ 48mDR6 @ 226 @ 276 @ 34
    106 @ 286 @ 336 @ 45NRDRj6 @ 236 @ 296 @ 38DR6 @ 226 @ 226 @ 28

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

    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 R404.1.2.3.7.6 and Table R404.1.2(9).

    4. d.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 #4@48 inches on center.

    5. e.Allowable deflection criterion is L/240, where L is the unsupported height of the basement wall in inches.

    6. f.Interpolation is not permitted.

    7. g.Where walls will retain 4 feet or more of unbalanced backfill, they shall be laterally supported at the top and bottom before backfilling.

    8. h.Vertical reinforcement shall be located to provide a cover of 1.25 inches measured from the inside face of the wall. The center of the steel shall not vary from the specified location by more than the greater of 10 percent of the wall thickness or 3/8-inch.

    9. i.Concrete cover for reinforcement measured from the inside face of the wall shall not be less than 3/4-inch. Concrete cover for reinforcement measured from the outside face of the wall shall not be less than 11/2 inches for No. 5 bars and smaller, and not less than 2 inches for larger bars.

    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.Concrete shall have a specified compressive strength, f′c, of not less than 2,500 psi at 28 days, unless a higher strength is required by footnote l or m.

    12. l.The minimum thickness is permitted to be reduced 2 inches, provided the minimum specified compressive strength of concrete, f′c, is 4,000 psi.

    13. m.A plain concrete wall with a minimum nominal thickness of 12 inches is permitted, provided minimum specified compressive strength of concrete, f′c, is 3,500 psi.

    14. n.See Table R611.3 for tolerance from nominal thickness permitted for flat walls.

    TABLE R404.1.2(9)

    MINIMUM SPACING FOR ALTERNATE BAR SIZE AND/OR ALTERNATE GRADE OF STEELa, b, c

    BAR SPACING FROM APPLICABLE TABLE IN SECTION R404.1.2.2 (inches)BAR SIZE FROM APPLICABLE TABLE IN SECTION R404.1.2.2
    #4#5#6
    Alternate bar size and/or alternate grade of steel desired
    Grade 60Grade 40Grade 60Grade 40Grade 60Grade 40
    #5#6#4#5#6#4#6#4#5#6#4#5#4#5#6
    Maximum spacing for alternate bar size and/or alternate grade of steel (inches)
    81218581251135846245
    91420691361346946346
    1016227101561447957357
    11172471116716571058357
    12192681218817581158468
    13202991319818691269469
    142231914219206913610479
    1523331016221021610147115710
    1625351117231023711157115811
    1726371118251124711168125811
    1828401219261226812178135812
    1929421320281227813189136913
    2031441321291328913199146913
    213346142231143091420101561014
    223448152332143191521101671015
    2336481524341533101522101671115
    2437481625351534101623111771116
    2539481726371635111724111881217
    2640481727381737111725121881217
    2742481828401738121826121981318
    2843481929411840121926132081319
    2945481930431941121927132091419
    3047482031441943132028142191420
    3148482132452044132129142291521
    32484821334721451421301523101521
    33484822344821471422311523101622
    34484823354822481523321524101623
    35484823364823481523331625111623
    36484824374823481524341625111724
    37484825384824481625351726111725
    38484825394825481625361727121825
    39484826404825481726371827121826
    40484827414826481727381828121927
    41484827424826481827391929121927
    42484828434827481828401930132028
    43484829444828481829412030132029
    44484829454828481929422031132129
    45484830474829481930432032142130
    46484831484830482031442132142231
    47484831484830482031442133142231
    48484832484831482132452234152332

    For SI: 1 inch = 25.4 mm, 1 pound per square inch = 6.895 kPa.

    1. a.This table is for use with tables in Section R404.1.2.2 that specify the minimum bar size and maximum spacing of vertical wall reinforcement for foundation walls and above-grade walls. Reinforcement specified in tables in Sections R404.1.2.2 is based on Grade 60 steel reinforcement.

    2. b.Bar spacing shall not exceed 48 inches on center and shall not be less than one-half the nominal wall thickness.

    3. c.For Grade 50 steel bars (ASTM A 996, Type R), use spacing for Grade 40 bars or interpolate between Grades 40 and 60.

    R404.1.2.1Concrete cross-section.

    Concrete walls constructed in accordance with this code shall comply with the shapes and minimum concrete cross-sectional dimensions required by Table R611.3. Other types of forming systems resulting in concrete walls not in compliance with this section and Table R611.3 shall be designed in accordance with ACI 318.

    R404.1.2.2Reinforcement for foundation walls.

    Concrete foundation walls shall be laterally supported at the top and bottom. Horizontal reinforcement shall be provided in accordance with Table R404.1.2(1). Vertical reinforcement shall be provided in accordance with Table R404.1.2(2), R404.1.2(3), R404.1.2(4), R404.1.2(5), R404.1.2(6), R404.1.2(7) or R404.1.2(8). Vertical reinforcement for flat basement walls retaining 4 feet (1219 mm) or more of unbalanced backfill is permitted to be determined in accordance with Table R404.1.2(9). For basement walls supporting above-grade concrete walls, vertical reinforcement shall be the greater of that required by Tables R404.1.2(2) through R404.1.2(8) or by Section R611.6 for the above-grade wall. In buildings assigned to Seismic Design Category D0, D1 or D2, concrete foundation walls shall also comply with Section R404.1.4.2.

    R404.1.2.2.1Concrete foundation stem walls supporting above-grade concrete walls.

    Foundation stem walls that support above-grade concrete walls shall be designed and constructed in accordance with this section.

    1. 1.Stem walls not laterally supported at top.Concrete stem walls that are not monolithic with slabs-on-ground or are not otherwise laterally supported by slabs-on-ground shall comply with this section. Where unbalanced backfill retained by the stem wall is less than or equal to 18 inches (457 mm), the stem wall and above-grade wall it supports shall be provided with vertical reinforcement in accordance with Section R611.6 and Table R611.6(1), R611.6(2) or R611.6(3) for above-grade walls. Where unbalanced backfill retained by the stem wall is greater than 18 inches (457 mm), the stem wall and above-grade wall it supports shall be provided with vertical reinforcement in accordance with Section R611.6 and Table R611.6(4).

    2. 2.Stem walls laterally supported at top.Concrete stem walls that are monolithic with slabs-on-ground or are otherwise laterally supported by slabs-on-ground shall be vertically reinforced in accordance with Section R611.6 and Table R611.6(1), R611.6(2) or R611.6(3) for above-grade walls. Where the unbalanced backfill retained by the stem wall is greater than 18 inches (457 mm), the connection between the stem wall and the slab-on-ground, and the portion of the slab-on-ground providing lateral support for the wall shall be designed in accordance with PCA 100 or in accordance with accepted engineering practice. Where the unbalanced backfill retained by the stem wall is greater than 18 inches (457 mm), the minimum nominal thickness of the wall shall be 6 inches (152 mm).

    R404.1.2.2.2Concrete foundation stem walls supporting light-frame above-grade walls.

    Concrete foundation stem walls that support light-frame above-grade walls shall be designed and constructed in accordance with this section.

    1. 1.Stem walls not laterally supported at top.Concrete stem walls that are not monolithic with slabs-on-ground or are not otherwise laterally supported by slabs-on-ground and retain 48 inches (1219 mm) or less of unbalanced fill, measured from the top of the wall, shall be constructed in accordance with Section R404.1.2. Foundation stem walls that retain more than 48 inches (1219 mm) of unbalanced fill, measured from the top of the wall, shall be designed in accordance with Sections R404.1.3 and R404.4.

    2. 2.Stem walls laterally supported at top.Concrete stem walls that are monolithic with slabs-on-ground or are otherwise laterally supported by slabs-on-ground shall be constructed in accordance with Section R404.1.2. Where the unbalanced backfill retained by the stem wall is greater than 48 inches (1219 mm), the connection between the stem wall and the slab-on-ground, and the portion of the slab-on-ground providing lateral support for the wall shall be designed in accordance with PCA 100 or in accordance with accepted engineering practice.

    R404.1.2.3Concrete, materials for concrete, and forms.

    Materials used in concrete, the concrete itself and forms shall conform to requirements of this section or ACI 318.

    R404.1.2.3.1Compressive strength.

    The minimum specified compressive strength of concrete, fc, shall comply with Section R402.2 and shall be not less than 2,500 psi (17.2 MPa) at 28 days in buildings assigned to Seismic Design Category A, B or C and 3000 psi (20.5 MPa) in buildings assigned to Seismic Design Category D0, D1 or D2.

    R404.1.2.3.2Concrete mixing and delivery.

    Mixing and delivery of concrete shall comply with ASTM C 94 or ASTM C 685.

    R404.1.2.3.3Maximum aggregate size.

    The nominal maximum size of coarse aggregate shall not exceed one-fifth the narrowest distance between sides of forms, or three-fourths the clear spacing between reinforcing bars or between a bar and the side of the form.

    Exception: When approved, these limitations shall not apply where removable forms are used and workability and methods of consolidation permit concrete to be placed without honeycombs or voids.

    R404.1.2.3.4Proportioning and slump of concrete.

    Proportions of materials for concrete shall be established to provide workability and consistency to permit concrete to be worked readily into forms and around reinforcement under conditions of placement to be employed, without segregation or excessive bleeding. Slump of concrete placed in removable forms shall not exceed 6 inches (152 mm).

    Exception: When approved, the slump is permitted to exceed 6 inches (152 mm) for concrete mixtures that are resistant to segregation, and are in accordance with the form manufacturer’s recommendations.

    Slump of concrete placed in stay-in-place forms shall exceed 6 inches (152 mm). Slump of concrete shall be determined in accordance with ASTM C 143.

    R404.1.2.3.5Consolidation of concrete.

    Concrete shall be consolidated by suitable means during placement and shall be worked around embedded items and reinforcement and into corners of forms. Where stay-in-place forms are used, concrete shall be consolidated by internal vibration.

    Exception: When approved for concrete to be placed in stay-in-place forms, self-consolidating concrete mixtures with slumps equal to or greater than 8 inches (203 mm) that are specifically designed for placement without internal vibration need not be internally vibrated.

    R404.1.2.3.6Form materials and form ties.

    Forms shall be made of wood, steel, aluminum, plastic, a composite of cement and foam insulation, a composite of cement and wood chips, or other approved material suitable for supporting and containing concrete. Forms shall provide sufficient strength to contain concrete during the concrete placement operation.

    Form ties shall be steel, solid plastic, foam plastic, a composite of cement and wood chips, a composite of cement and foam plastic, or other suitable material capable of resisting the forces created by fluid pressure of fresh concrete.

    R404.1.2.3.6.1Stay-in-place forms.

    Stay-in-place concrete forms shall comply with this section.

    1. 1.Surface burning characteristics. The flame-spread index and smoke-developed index of forming material, other than foam plastic, left exposed on the interior shall comply with Section R302. The surface burning characteristics of foam plastic used in insulating concrete forms shall comply with Section R316.3.

    2. 2.Interior covering. Stay-in-place forms constructed of rigid foam plastic shall be protected on the interior of the building as required by Section R316. Where gypsum board is used to protect the foam plastic, it shall be installed with a mechanical fastening system. Use of adhesives in addition to mechanical fasteners is permitted.

    3. 3.Exterior wall covering. Stay-in-place forms constructed of rigid foam plastics shall be protected from sunlight and physical damage by the application of an approved exterior wall covering complying with this code. Exterior surfaces of other stay-in-place forming systems shall be protected in accordance with this code.

    4. 4.Termite hazards. In areas where hazard of termite damage is very heavy in accordance with Figure R301.2(6), foam plastic insulation shall be permitted below grade on foundation walls in accordance with one of the following conditions:

      1. 4.1.Where in addition to the requirements in Section R318.1, an approved method of protecting the foam plastic and structure from subterranean termite damage is provided.

      2. 4.2.The structural members of walls, floors, ceilings and roofs are entirely of noncombustible materials or pressure-preservative-treated wood.

      3. 4.3.On the interior side of basement walls.

    5. 5.Flat ICF wall system forms shall conform to ASTM E 2634

    R404.1.2.3.7Reinforcement.

    R404.1.2.3.7.1Steel 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. In buildings assigned to Seismic Design Category A, B or C, the minimum yield strength of reinforcing steel shall be 40,000 psi (Grade 40) (276 MPa). In buildings assigned to Seismic Design Category D0, D1 or D2, reinforcing steel shall comply with the requirements of ASTM A 706 for low-alloy steel with a minimum yield strength of 60,000 psi (Grade 60) (414 MPa).

    R404.1.2.3.7.2Location of reinforcement in wall.

    The center of vertical reinforcement in basement walls determined from Tables R404.1.2(2) through R404.1.2(7) shall be located at the centerline of the wall. Vertical reinforcement in basement walls determined from Table R404.1.2(8) shall be located to provide a maximum cover of 1.25 inches (32 mm) measured from the inside face of the wall. Regardless of the table used to determine vertical wall reinforcement, the center of the steel shall not vary from the specified location by more than the greater of 10 percent of the wall thickness and 3/8-inch (10 mm). Horizontal and vertical reinforcement shall be located in foundation walls to provide the minimum cover required by Section R404.1.2.3.7.4.

    R404.1.2.3.7.3Wall openings.

    Vertical wall reinforcement required by Section R404.1.2.2 that is interrupted by wall openings shall have additional vertical reinforcement of the same size placed within 12 inches (305 mm) of each side of the opening.

    R404.1.2.3.7.4Support 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). The minus tolerance for cover shall not exceed the smaller of one-third the required cover or 3/8 inch (10 mm).

    R404.1.2.3.7.5Lap splices.

    Vertical and horizontal wall reinforcement shall be the longest lengths practical. Where splices are necessary in reinforcement, the length of lap splice shall be in accordance with Table R611.5.4.(1) and Figure R611.5.4(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 R611.5.4(1).

    R404.1.2.3.7.6Alternate grade of reinforcement and spacing.

    Where tables in Section R404.1.2.2 specify vertical wall reinforcement based on minimum bar size and maximum spacing, which are based on Grade 60 (414 MPa) steel reinforcement, different size bars and/or bars made from a different grade of steel are permitted provided an equivalent area of steel per linear foot of wall is provided. Use of Table R404.1.2(9) is permitted to determine the maximum bar spacing for different bar sizes than specified in the tables and/or bars made from a different grade of steel. Bars shall not be spaced less than one-half the wall thickness, or more than 48 inches (1219 mm) on center.

    R404.1.2.3.7.7Standard hooks.

    Where reinforcement is required by this code to terminate with a standard hook, the hook shall comply with Section R611.5.4.5 and Figure R611.5.4(3).

    R404.1.2.3.7.8Construction joint reinforcement.

    Construction joints in foundation walls shall be made and located to not impair the strength of the wall. Construction joints in plain concrete walls, including walls required to have not less than No. 4 bars at 48 inches (1219 mm) on center by Sections R404.1.2.2 and R404.1.4.2, shall be located at points of lateral support, and a minimum of one No. 4 bar shall extend across the construction joint at a spacing not to exceed 24 inches (610 mm) on center. Construction joint reinforcement shall have a minimum of 12 inches (305 mm) embedment on both sides of the joint. Construction joints in reinforced concrete walls shall be located in the middle third of the span between lateral supports, or located and constructed as required for joints in plain concrete walls.

    Exception: Use of vertical wall reinforcement required by this code is permitted in lieu of construction joint reinforcement provided the spacing does not exceed 24 inches (610 mm), or the combination of wall reinforcement and No.4 bars described above does not exceed 24 inches (610 mm).

    R404.1.2.3.8Exterior wall coverings.

    Requirements for installation of masonry veneer, stucco and other wall coverings on the exterior of concrete walls and other construction details not covered in this section shall comply with the requirements of this code.

    R404.1.2.4Requirements for Seismic Design Category C.

    Concrete foundation walls supporting above-grade concrete walls in townhouses assigned to Seismic Design Category C shall comply with ACI 318, ACI 332 or PCA 100 (see Section R404.1.2).

    R404.1.3Design required.

    Concrete or masonry foundation walls shall be designed in accordance with accepted engineering practice when either of the following conditions exists:

    1. 1.Walls are subject to hydrostatic pressure from groundwater.

    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.

      Exception: Cantilevered concrete and masonry foundation walls constructed in accordance with Table R404.1.1(5), R404.1.1(6), or R404.1.1(7).

    R404.1.4Seismic Design Category D0, D1 or D2.

    R404.1.4.1Masonry foundation walls.

    In addition to the requirements of Table R404.1.1(1) plain masonry foundation walls in buildings assigned to Seismic Design Category D0, D1 or D2, as established in Table R301.2(1), shall comply with the following.

    1. 1.Wall height shall not exceed 8 feet (2438 mm).

    2. 2.Unbalanced backfill height shall not exceed 4 feet (1219 mm).

    3. 3.Minimum nominal thickness for plain masonry foundation walls shall be 8 inches (203 mm).

    4. 4.Masonry stem walls shall have a minimum vertical reinforcement of one No. 3 (No. 10) bar located a maximum of 4 feet (1219 mm) on center in grouted cells. Vertical reinforcement shall be tied to the horizontal reinforcement in the footings.

    Foundation walls in buildings assigned to Seismic Design Category D0, D1 or D2, as established in Table R301.2(1), supporting more than 4 feet (1219 mm) of unbalanced backfill or exceeding 8 feet (2438 mm) in height shall be constructed in accordance with Table R404.1.1(2), R404.1.1(3) or R404.1.1(4). Masonry foundation walls shall have two No. 4 (No. 13) horizontal bars located in the upper 12 inches (305 mm) of the wall.

    R404.1.4.2Concrete foundation walls.

    In buildings assigned to Seismic Design Category D0, D1 or D2, as established in Table R301.2(1), concrete foundation walls that support light-frame walls shall comply with this section, and concrete foundation walls that support above-grade concrete walls shall comply with ACI 318, ACI 332 or PCA 100 (see Section R404.1.2). In addition to the horizontal reinforcement required by Table R404.1.2(1), plain concrete walls supporting light-frame walls shall comply with the following.

    1. 1.Wall height shall not exceed 8 feet (2438 mm).

    2. 2.Unbalanced backfill height shall not exceed 4 feet (1219 mm).

    3. 3.Minimum thickness for plain concrete foundation walls shall be 7.5 inches (191 mm) except that 6 inches (152 mm) is permitted where the maximum wall height is 4 feet, 6 inches (1372 mm).

    Foundation walls less than 7.5 inches (191 mm) in thickness, supporting more than 4 feet (1219 mm) of unbalanced backfill or exceeding 8 feet (2438 mm) in height shall be provided with horizontal reinforcement in accordance with Table R404.1.2(1), and vertical reinforcement in accordance with Table R404.1.2(2), R404.1.2(3), R404.1.2(4), R404.1.2(5), R404.1.2(6), R404.1.2(7) or R404.1.2(8). Where Tables R404.1.2(2) through R404.1.2(8) permit plain concrete walls, not less than No. 4 (No. 13) vertical bars at a spacing not exceeding 48 inches (1219 mm) shall be provided.

    R404.1.5Foundation wall thickness based on walls supported.

    The thickness of masonry or concrete foundation walls shall not be less than that required by Section R404.1.5.1 or R404.1.5.2, respectively.

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 degree = 0.0175 rad.

    FIGURE R404.1.5(1)

    FOUNDATION WALL CLAY MASONRY CURTAIN WALL WITH CONCRETE MASONRY PIERS

    R404.1.5.1Masonry wall thickness.

    Masonry foundation walls shall not be less than the thickness of the wall supported, except that masonry foundation walls of at least 8-inch (203 mm) nominal thickness shall be permitted under brick veneered frame walls and under 10-inch-wide (254 mm) cavity walls where the total height of the wall supported, including gables, is not more than 20 feet (6096 mm), provided the requirements of Section R404.1.1 are met.

    R404.1.5.2Concrete wall thickness.

    The thickness of concrete foundation walls shall be equal to or greater than the thickness of the wall in the story above. Concrete foundation walls with corbels, brackets or other projections built into the wall for support of masonry veneer or other purposes are not within the scope of the tables in this section.

    Where a concrete foundation wall is reduced in thickness to provide a shelf for the support of masonry veneer, the reduced thickness shall be equal to or greater than the thickness of the wall in the story above. Vertical reinforcement for the foundation wall shall be based on Table R404.1.2(8) and located in the wall as required by Section R404.1.2.3.7.2 where that table is used. Vertical reinforcement shall be based on the thickness of the thinner portion of the wall.

    Exception: Where the height of the reduced thickness portion measured to the underside of the floor assembly or sill plate above is less than or equal to 24 inches (610 mm) and the reduction in thickness does not exceed 4 inches (102 mm), the vertical reinforcement is permitted to be based on the thicker portion of the wall.

    R404.1.5.3Pier and curtain wall foundations.

    Use of pier and curtain wall foundations shall be permitted to support light-frame construction not more than two stories in height, provided the following requirements are met:

    1. 1.All load-bearing walls shall be placed on continuous concrete footings placed integrally with the exterior wall footings.

    2. 2.The minimum actual thickness of a load-bearing masonry wall shall be not less than 4 inches (102 mm) nominal or 33/8 inches (92 mm) actual thickness, and shall be bonded integrally with piers spaced in accordance with Section R606.9.

    3. 3.Piers shall be constructed in accordance with Section R606.6 and Section R606.6.1, and shall be bonded into the load-bearing masonry wall in accordance with Section R608.1.1 or R608.1.1.2.

    4. 4.The maximum height of a 4-inch (102 mm) load-bearing masonry foundation wall supporting wood-frame walls and floors shall not be more than 4 feet (1219 mm).

    5. 5.Anchorage shall be in accordance with Section R403.1.6, Figure R404.1.5(1), or as specified by engineered design accepted by the building official.

    6. 6.The unbalanced fill for 4-inch (102 mm) foundation walls shall not exceed 24 inches (610 mm) for solid masonry or 12 inches (305 mm) for hollow masonry.

    7. 7.In Seismic Design Categories D0, D1 and D2, prescriptive reinforcement shall be provided in the horizontal and vertical direction. Provide minimum horizontal joint reinforcement of two No. 9 gage wires spaced not less than 6 inches (152 mm) or one 1/4 inch (6.4 mm) diameter wire at 10 inches (254 mm) on center vertically. Provide minimum vertical reinforcement of one No. 4 bar at 48 inches (1220 mm) on center horizontally grouted in place.

    R404.1.6Height above finished grade.

    Concrete and masonry foundation walls shall extend above the finished grade adjacent to the foundation at all points a minimum of 4 inches (102 mm) where masonry veneer is used and a minimum of 6 inches (152 mm) elsewhere.

    R404.1.7Backfill placement.

    Backfill shall not be placed against the wall until the wall has sufficient strength and has been anchored to the floor above, or has been sufficiently braced to prevent damage by the backfill.

    Exception: Bracing is not required for walls supporting less than 4 feet (1219 mm) of unbalanced backfill.

    R404.1.8Rubble stone masonry.

    Rubble stone masonry foundation walls shall have a minimum thickness of 16 inches (406 mm), shall not support an unbalanced backfill exceeding 8 feet (2438 mm) in height, shall not support a soil pressure greater than 30 pounds per square foot per foot (4.71 kPa/m), and shall not be constructed in Seismic Design Categories D0, D1, D2 or townhouses in Seismic Design Category C, as established in Figure R301.2(2).

    R404.1.9Isolated masonry piers.

    Isolated masonry piers shall be constructed in accordance with this section and the general masonry construction requirements of Section R606. Hollow masonry piers shall have a minimum nominal thickness of 8 inches (203 mm), with a nominal height not exceeding four times the nominal thickness and a nominal length not exceeding three times the nominal thickness. Where hollow masonry units are solidly filled with concrete or grout, piers shall be permitted to have a nominal height not exceeding ten times the nominal thickness. Footings for isolated masonry piers shall be sized in accordance with Section R403.1.1.

    R404.1.9.1Pier cap.

    Hollow masonry piers shall be capped with 4 inches (102 mm) of solid masonry or concrete, a masonry cap block, or shall have cavities of the top course filled with concrete or grout. Where required, termite protection for the pier cap shall be provided in accordance with Section R318.

    R404.1.9.2Masonry piers supporting floor girders.

    Masonry piers supporting wood girders sized in accordance with Tables R502.5(1) and R502.5(2) shall be permitted in accordance with this section. Piers supporting girders for interior bearing walls shall have a minimum nominal dimension of 12 inches (305 mm) and a maximum height of 10 feet (3048 mm) from top of footing to bottom of sill plate or girder. Piers supporting girders for exterior bearing walls shall have a minimum nominal dimension of 12 inches (305 mm) and a maximum height of 4 feet (1220 mm) from top of footing to bottom of sill plate or girder. Girders and sill plates shall be anchored to the pier or footing in accordance with Section R403.1.6 or Figure R404.1.5(1). Floor girder bearing shall be in accordance with Section R502.6.

    R404.1.9.3Masonry piers supporting braced wall panels.

    Masonry piers supporting braced wall panels shall be designed in accordance with accepted engineering practice.

    R404.1.9.4Seismic design of masonry piers.

    Masonry piers in all dwellings located in Seismic Design Category D0, D1 or D2, and townhouses in Seismic Design Category C, shall be designed in accordance with accepted engineering practice.

    R404.1.9.5Masonry piers in flood hazard areas.

    Masonry piers for dwellings in flood hazard areas shall be designed in accordance with Section R322.

    R404.2Wood foundation walls.

    Wood foundation walls shall be constructed in accordance with the provisions of Sections R404.2.1 through R404.2.6 and with the details shown in Figures R403.1(2) and R403.1(3).

    R404.2.1Identification.

    All load-bearing lumber shall be identified by the grade mark of a lumber grading or inspection agency which has been approved by an accreditation body that complies with DOC PS 20. In lieu of a grade mark, a certificate of inspection issued by a lumber grading or inspection agency meeting the requirements of this section shall be accepted. Wood structural panels shall conform to DOC PS 1 or DOC PS 2 and shall be identified by a grade mark or certificate of inspection issued by an approved agency.

    R404.2.2Stud size.

    The studs used in foundation walls shall be 2-inch by 6-inch (51 mm by 152 mm) members. When spaced 16 inches (406 mm) on center, a wood species with an Fb value of not less than 1,250 pounds per square inch (8619 kPa) as listed in AF&PA/NDS shall be used. When spaced 12 inches (305 mm) on center, an Fb of not less than 875 psi (6033 kPa) shall be required.

    R404.2.3Height of backfill.

    For wood foundations that are not designed and installed in accordance with AF&PA PWF, the height of backfill against a foundation wall shall not exceed 4 feet (1219 mm). When the height of fill is more than 12 inches (305 mm) above the interior grade of a crawl space or floor of a basement, the thickness of the plywood sheathing shall meet the requirements of Table R404.2.3.

    TABLE R404.2.3

    PLYWOOD GRADE AND THICKNESS FOR WOOD FOUNDATION CONSTRUCTION (30 pcf equivalent-fluid weight soil pressure)

    HEIGHT OF FILL (inches)STUD SPACING (inches)FACE GRAIN ACROSS STUDSFACE GRAIN PARALLEL TO STUDS
    GradeaMinimum thickness (inches)Span ratingGradeaMinimum thickness (inches)b, cSpan rating
    2412B15/3232/16A15/3232/16
    B15/32c32/16
    16B15/3232/16A15/32c32/16
    B19/32c (4, 5 ply)40/20
    3612B15/3232/16A15/3232/16
    B15/32c (4, 5 ply)32/16
    B19/32 (4, 5 ply)40/20
    16B15/32c32/16A19/3240/20
    B23/3248/24
    4812B15/3232/16A15/32c32/16
    B19/32c(4, 5 ply)40/20
    16B19/3240/20A19/32c40/20
    A23/3248/24

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per cubic foot = 0.1572 kN/m3.

    1. a.Plywood shall be of the following minimum grades in accordance with DOC PS 1 or DOC PS 2:

      1. 1.DOC PS 1 Plywood grades marked:

        1. 1.1.Structural I C-D (Exposure 1).

        2. 1.2.C-D (Exposure 1).

      2. 2.DOC PS 2 Plywood grades marked:

        1. 2.1.Structural I Sheathing (Exposure 1).

        2. 2.2.Sheathing (Exposure 1).

      3. 3.Where a major portion of the wall is exposed above ground and a better appearance is desired, the following plywood grades marked exterior are suitable:

        1. 3.1.Structural I A-C, Structural I B-C or Structural I C-C (Plugged) in accordance with DOC PS 1.

        2. 3.2.A-C Group 1, B-C Group 1, C-C (Plugged) Group 1 or MDO Group 1 in accordance with DOC PS 1.

        3. 3.3.Single Floor in accordance with DOC PS 1 or DOC PS 2.

    2. b.Minimum thickness 15/32 inch, except crawl space sheathing may be 3/8 inch for face grain across studs 16 inches on center and maximum 2-foot depth of unequal fill.

    3. c.For this fill height, thickness and grade combination, panels that are continuous over less than three spans (across less than three stud spacings) require blocking 16 inches above the bottom plate. Offset adjacent blocks and fasten through studs with two 16d corrosion-resistant nails at each end.

    R404.2.4Backfilling.

    Wood foundation walls shall not be backfilled until the basement floor and first floor have been constructed or the walls have been braced. For crawl space construction, backfill or bracing shall be installed on the interior of the walls prior to placing backfill on the exterior.

    R404.2.5Drainage and dampproofing.

    Wood foundation basements shall be drained and dampproofed in accordance with Sections R405 and R406, respectively.

    R404.2.6Fastening.

    Wood structural panel foundation wall sheathing shall be attached to framing in accordance with Table R602.3(1) and Section R402.1.1.

    R404.3Wood sill plates.

    Wood sill plates shall be a minimum of 2-inch by 4-inch (51 mm by 102 mm) nominal lumber. Sill plate anchorage shall be in accordance with Sections R403.1.6 and R602.11.

    R404.4Retaining walls.

    Retaining walls that are not laterally supported at the top and that retain in excess of 24 inches (610 mm) of unbalanced fill shall be designed to ensure stability against overturning, sliding, excessive foundation pressure and water uplift. Retaining walls shall be designed for a safety factor of 1.5 against lateral sliding and overturning.

    R404.5Precast concrete foundation walls.

    R404.5.1Design.

    Precast concrete foundation walls shall be designed in accordance with accepted engineering practice. The design and manufacture of precast concrete foundation wall panels shall comply with the materials requirements of Section R402.3 or ACI 318. The panel design drawings shall be prepared by a registered design professional where required by the statutes of the jurisdiction in which the project is to be constructed in accordance with Section R106.1.

    R404.5.2Precast concrete foundation design drawings.

    Precast concrete foundation wall design drawings shall be submitted to the building official and approved prior to installation. Drawings shall include, at a minimum, the information specified below:

    1. 1.Design loading as applicable;

    2. 2.Footing design and material;

    3. 3.Concentrated loads and their points of application;

    4. 4.Soil bearing capacity;

    5. 5.Maximum allowable total uniform load;

    6. 6.Seismic design category; and

    7. 7.Basic wind speed.

    R404.5.3Identification.

    Precast concrete foundation wall panels shall be identified by a certificate of inspection label issued by an approved third party inspection agency.

    SECTIONR405
    FOUNDATION DRAINAGE

    R405.1Concrete or masonry foundations.

    Drains shall be provided around all concrete or masonry foundations that retain earth and enclose habitable or usable spaces located below grade. Drainage tiles, gravel or crushed stone drains, perforated pipe or other approved systems or materials shall be installed at or below the area to be protected and shall discharge by gravity or mechanical means into an approved drainage system. Gravel or crushed stone drains shall extend at least 1 foot (305 mm) beyond the outside edge of the footing and 6 inches (152 mm) above the top of the footing and be covered with an approved filter membrane material. The top of open joints of drain tiles shall be protected with strips of building paper. Perforated drains shall be surrounded with an approved filter membrane or the filter membrane shall cover the washed gravel or crushed rock covering the drain. Drainage tiles or perforated pipe shall be placed on a minimum of 2 inches (51 mm) of washed gravel or crushed rock at least one sieve size larger than the tile joint opening or perforation and covered with not less than 6 inches (152 mm) of the same material.

    Exception: A drainage system is not required when the foundation is installed on well-drained ground or sand-gravel mixture soils according to the Unified Soil Classification System, Group I Soils, as detailed in Table R405.1.

    TABLE R405.1

    PROPERTIES OF SOILS CLASSIFIED ACCORDING TO THE UNIFIED SOIL CLASSIFICATION SYSTEM

    SOIL GROUPUNIFIED SOIL CLASSIFICATION SYSTEM SYMBOLSOIL DESCRIPTIONDRAINAGE CHARACTERISTICSaFROST HEAVE POTENTIALVOLUME CHANGE POTENTIAL EXPANSIONb
    Group IGWWell-graded gravels, gravel sand mixtures, little or no finesGoodLowLow
    GPPoorly graded gravels or gravel sand mixtures, little or no finesGoodLowLow
    SWWell-graded sands, gravelly sands, little or no finesGoodLowLow
    SPPoorly graded sands or gravelly sands, little or no finesGoodLowLow
    GMSilty gravels, gravel-sand-silt mixturesGoodMediumLow
    SMSilty sand, sand-silt mixturesGoodMediumLow
    Group IIGCClayey gravels, gravel-sand-clay mixturesMediumMediumLow
    SCClayey sands, sand-clay mixtureMediumMediumLow
    MLInorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with slight plasticityMediumHighLow
    CLInorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean claysMediumMediumMedium to Low
    Group IIICHInorganic clays of high plasticity, fat claysPoorMediumHigh
    MHInorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic siltsPoorHighHigh
    Group IVOLOrganic silts and organic silty clays of low plasticityPoorMediumMedium
    OHOrganic clays of medium to high plasticity, organic siltsUnsatisfactoryMediumHigh
    PtPeat and other highly organic soilsUnsatisfactoryMediumHigh

    For SI: 1 inch = 25.4 mm.

    1. a.The percolation rate for good drainage is over 4 inches per hour, medium drainage is 2 inches to 4 inches per hour, and poor is less than 2 inches per hour.

    2. b.Soils with a low potential expansion typically have a plasticity index (PI) of 0 to 15, soils with a medium potential expansion have a PI of 10 to 35 and soils with a high potential expansion have a PI greater than 20.

    R405.1.1Precast concrete foundation.

    Precast concrete walls that retain earth and enclose habitable or useable space located below-grade that rest on crushed stone footings shall have a perforated drainage pipe installed below the base of the wall on either the interior or exterior side of the wall, at least one foot (305 mm) beyond the edge of the wall. If the exterior drainage pipe is used, an approved filter membrane material shall cover the pipe. The drainage system shall discharge into an approved sewer system or to daylight.

    R405.2Wood foundations.

    Wood foundations enclosing habitable or usable spaces located below grade shall be adequately drained in accordance with Sections R405.2.1 through R405.2.3.

    R405.2.1Base.

    A porous layer of gravel, crushed stone or coarse sand shall be placed to a minimum thickness of 4 inches (102 mm) under the basement floor. Provision shall be made for automatic draining of this layer and the gravel or crushed stone wall footings.

    R405.2.2Vapor retarder.

    A 6-mil-thick (0.15 mm) polyethylene vapor retarder shall be applied over the porous layer with the basement floor constructed over the polyethylene.

    R405.2.3Drainage system.

    In other than Group I soils, a sump shall be provided to drain the porous layer and footings. The sump shall be at least 24 inches (610 mm) in diameter or 20 inches square (0.0129 m2), shall extend at least 24 inches (610 mm) below the bottom of the basement floor and shall be capable of positive gravity or mechanical drainage to remove any accumulated water. The drainage system shall discharge into an approved sewer system or to daylight.

    SECTIONR406
    FOUNDATION WATERPROOFING
    AND DAMPPROOFING

    R406.1Concrete and masonry foundation dampproofing.

    (This section deleted in its entirety. See MR1309.0406.)

    R406.2Concrete and masonry foundation waterproofing.

    Exterior foundation walls that retain earth and enclose below grade interior spaces, floors, and crawl spaces shall be waterproofed. Waterproofing shall be installed at a minimum from the top of the footing to the finished grade or in accordance with the manufacturer’s installation instructions. Walls shall be waterproofed in accordance with one of the following:

    1. 1.2-ply hot-mopped felts.

    2. 2.55-pound (25 kg) roll roofing.

    3. 3.6-mil (0.15 mm) polyvinyl chloride.

    4. 4.6-mil (0.15 mm) polyethylene.

    5. 5.40-mil (1 mm) polymer-modified asphalt.

    6. 6.60-mil (1.5 mm) flexible polymer cement.

    7. 7.1/8-inch (3 mm) cement-based, fiber-reinforced, waterproof coating.

    8. 8.60-mil (1.5 mm) solvent-free liquid-applied synthetic rubber.

    Exception: Organic solvent-based products such as hydrocarbons, chlorinated hydrocarbons, ketones, and esters shall not be used for ICF walls with expanded polystyrene form material. Use of plastic roofing cements, acrylic coatings, latex coatings, mortars, and pargings to seal ICF walls is permitted. Cold-setting asphalt or hot asphalt shall conform to Type C of ASTM D 449. Hot asphalt shall be applied at a temperature of less than 200°F (90°C).

    All joints in membrane waterproofing shall be lapped and sealed with an adhesive compatible with the membrane.

    R406.3Dampproofing for wood foundations.

    Wood foundations enclosing habitable or usable spaces located below grade shall be dampproofed in accordance with Sections R406.3.1 through R406.3.4.

    R406.3.1Panel joint sealed.

    Plywood panel joints in the foundation walls shall be sealed full length with a caulking compound capable of producing a moisture-proof seal under the conditions of temperature and moisture content at which it will be applied and used.

    R406.3.2Below-grade moisture barrier.

    A 6-mil-thick (0.15 mm) polyethylene film shall be applied over the below-grade portion of exterior foundation walls prior to backfilling. Joints in the polyethylene film shall be lapped 6 inches (152 mm) and sealed with adhesive. The top edge of the polyethylene film shall be bonded to the sheathing to form a seal. Film areas at grade level shall be protected from mechanical damage and exposure by a pressure preservatively treated lumber or plywood strip attached to the wall several inches above finish grade level and extending approximately 9 inches (229 mm) below grade. The joint between the strip and the wall shall be caulked full length prior to fastening the strip to the wall. Other coverings appropriate to the architectural treatment may also be used. The polyethylene film shall extend down to the bottom of the wood footing plate but shall not overlap or extend into the gravel or crushed stone footing.

    R406.3.3Porous fill.

    The space between the excavation and the foundation wall shall be backfilled with the same material used for footings, up to a height of 1 foot (305 mm) above the footing for well-drained sites, or one-half the total back-fill height for poorly drained sites. The porous fill shall be covered with strips of 30-pound (13.6 kg) asphalt paper or 6-mil (0.15 mm) polyethylene to permit water seepage while avoiding infiltration of fine soils.

    R406.3.4Backfill.

    The remainder of the excavated area shall be backfilled with the same type of soil as was removed during the excavation.

    R406.4Precast concrete foundation system dampproofing.

    Except where required by Section R406.2 to be waterproofed, precast concrete foundation walls enclosing habitable or useable spaces located below grade shall be dampproofed in accordance with Section R406.1.

    R406.4.1Panel joints sealed.

    Precast concrete foundation panel joints shall be sealed full height with a sealant meeting ASTM C 920, Type S or M, Grade NS, Class 25, Use NT, M or A. Joint sealant shall be installed in accordance with the manufacturer’s installation instructions.

    SECTIONR407
    COLUMNS

    R407.1Wood column protection.

    Wood columns shall be protected against decay as set forth in Section R317.

    R407.2Steel column protection.

    All surfaces (inside and outside) of steel columns shall be given a shop coat of rust-inhibitive paint, except for corrosion-resistant steel and steel treated with coatings to provide corrosion resistance.

    R407.3Structural requirements.

    The columns shall be restrained to prevent lateral displacement at the bottom end. Wood columns shall not be less in nominal size than 4 inches by 4 inches (102 mm by 102 mm). Steel columns shall not be less than 3-inch-diameter (76 mm) Schedule 40 pipe manufactured in accordance with ASTM A 53 Grade B or approved equivalent.

    Exception: In Seismic Design Categories A, B and C, columns no more than 48 inches (1219 mm) in height on a pier or footing are exempt from the bottom end lateral displacement requirement within under-floor areas enclosed by a continuous foundation.

    SECTIONR408
    UNDER-FLOOR SPACE

    R408.1Ventilation.

    The under-floor space between the bottom of the floor joists and the earth under any building (except space occupied by a basement) shall have ventilation openings through foundation walls or exterior walls. The minimum net area of ventilation openings shall not be less than 1 square foot (0.0929 m2) for each 150 square feet (14 m2) of under-floor space area, unless the ground surface is covered by a Class 1 vapor retarder material. When a Class 1 vapor retarder material is used, the minimum net area of ventilation openings shall not be less than 1 square foot (0.0929 m2) for each 1,500 square feet (140 m2) of under-floor space area. One such ventilating opening shall be within 3 feet (914 mm) of each corner of the building.

    R408.2Openings for under-floor ventilation.

    The minimum net area of ventilation openings shall not be less than 1 square foot (0.0929 m2) for each 150 square feet (14 m2) of under-floor area. One ventilation opening shall be within 3 feet (915 mm) of each corner of the building. Ventilation openings shall be covered for their height and width with any of the following materials provided that the least dimension of the covering shall not exceed 1/4 inch (6.4 mm):

    1. 1.Perforated sheet metal plates not less than 0.070 inch (1.8 mm) thick.

    2. 2.Expanded sheet metal plates not less than 0.047 inch (1.2 mm) thick.

    3. 3.Cast-iron grill or grating.

    4. 4.Extruded load-bearing brick vents.

    5. 5.Hardware cloth of 0.035 inch (0.89 mm) wire or heavier.

    6. 6.Corrosion-resistant wire mesh, with the least dimension being 1/8 inch (3.2 mm) thick.

    Exception: The total area of ventilation openings shall be permitted to be reduced to 1/1,500 of the under-floor area where the ground surface is covered with an approved Class I vapor retarder material and the required openings are placed to provide cross ventilation of the space. The installation of operable louvers shall not be prohibited.

    R408.3Unvented crawl space.

    Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where:

    1. 1.Exposed earth is covered with a continuous Class I vapor retarder. Joints of the vapor retarder shall overlap by 6 inches (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (152 mm) up the stem wall and shall be attached and sealed to the stem wall or insulation; and

    2. 2.One of the following is provided for the under-floor space:

      1. 2.1.Continuously operated mechanical exhaust ventilation at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7m2) of crawlspace floor area, including an air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1103.2.1 of this code;

      2. 2.2.Conditioned air supply sized to deliver at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7 m2) of under-floor area, including a return air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2 of this code;

      3. 2.3.Plenum in existing structures complying with Section M1601.5, if under-floor space is used as a plenum.

    R408.4Access.

    Access shall be provided to all under-floor spaces. Access openings through the floor shall be a minimum of 18 inches by 24 inches (457 mm by 610 mm). Openings through a perimeter wall shall be not less than 16 inches by 24 inches (407 mm by 610 mm). When any portion of the through-wall access is below grade, an areaway not less than 16 inches by 24 inches (407 mm by 610 mm) shall be provided. The bottom of the areaway shall be below the threshold of the access opening. Through wall access openings shall not be located under a door to the residence. See Section M1305.1.4 for access requirements where mechanical equipment is located under floors.

    R408.5Removal of debris.

    The under-floor grade shall be cleaned of all vegetation and organic material. All wood forms used for placing concrete shall be removed before a building is occupied or used for any purpose. All construction materials shall be removed before a building is occupied or used for any purpose.

    R408.6Finished grade.

    The finished grade of under-floor surface may be located at the bottom of the footings; however, where there is evidence that the groundwater table can rise to within 6 inches (152 mm) of the finished floor at the building perimeter or where there is evidence that the surface water does not readily drain from the building site, the grade in the under-floor space shall be as high as the outside finished grade, unless an approved drainage system is provided.

    R408.7(Deleted)

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