The provisions of this chapter shall control the alteration, repair, addition and change of occupancy or relocation of existing buildings and structures, including historic buildings and structures as referenced in Section 301.1.1.
Exception: Existing bleachers, grandstands and folding and telescopic seating shall comply with ICC 300.
Alterations, repairs, additions and changes of occupancy to or relocation of, existing buildings and structures shall comply with the provisions of this chapter or with one of the methods provided in Section 301.1.
Building materials and systems shall comply with the requirements of this section.
Materials already in use in a building in compliance with requirements or approvals in effect at the time of their erection or installation shall be permitted to remain in use unless determined by the building official to be unsafe per Section 115.
Except as otherwise required or permitted by this code, materials permitted by the applicable code for new construction shall be used. Like materials shall be permitted for repairs and alterations, provided no hazard to life, health or property is created. Hazardous materials shall not be used where the code for new construction would not permit their use in buildings of similar occupancy, purpose and location.
Where the existing seismic force-resisting system is a type that can be designated ordinary, values of R, Ω0 and Cd for the existing seismic force-resisting system shall be those specified by the International Building Code for an ordinary system unless it is demonstrated that the existing system will provide performance equivalent to that of a detailed, intermediate or special system.
The building official shall have the authority to require the elimination of conditions deemed dangerous.