San Francisco Building Inspection Commission Codes § 3107.4 Design

The design shall make allowances for the effects of corrosion and lack of maintenance.

No anchor or support of any sign shall be connected to, or suspended by, an unbraced parapet wall, unless such wall is designed in accordance with the requirements for parapet walls specified in Chapter 16.

Fasteners and braces shall be of noncombustible construction, except that stringers for attachment of roof signs may be of 6-inch (152.4 mm) minimum dimension redwood or approved preservative-treated lumber.