503.11 Substantial structural alteration.

503.11 Substantial structural alteration. Where [ ← ] work involves a substantial structural alteration, the lateral load-resisting system of the

← altered building shall satisfy the requirements of Sections 1609 and 1613 of the [ ] San Francisco Building Code. Reduced seismic forces shall be permitted.

Exceptions:

1. Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes that are altered based on the conventional light-frame construction methods of the [ ← ] San Francisco Building Code. [ ← ]

2. Where the intended alteration involves only the lowest story of a building and Section 506 does not apply, only the lateral load-resisting components in and below that story need comply with this section.

503.11.1 Add the following section:

503.11.1 Non-structural alterations. Whenever alteration work in a building or structure involves substantial changes to elements such as walls, partitions or ceilings, on 2/3 or more of the number of stories excluding basements, the building or structure as a whole shall comply with Section 304.4. The term “substantial change” includes the addition, removal, repair or modification of such elements. All such work included in alteration permits issued within two years of the date of a permit application shall be included in the determination of whether the application is proposing substantial change to the building or structure.

Removal and replacement of interior gypboard or plaster in Type V (wood framed) R3 occupancy (one or two residential units) is not to be considered as “Substantial Change”.

The replacement gypboard must be 5/8" Type X with 5d cooler nails @ 4 inches on center or equivalent screws.