Los Angeles Municipal Code § 91.5.500 BASIC PROVISIONS.
SEC. 91.5.500. BASIC PROVISIONS.
Chapter 5 of the CRC is hereby adopted by reference with the following exceptions, modifications and additions.
91.5.503.2.4. Openings in Horizontal Diaphragms. (Amended by Ord. No. 188,797, Eff. 12/31/25.) Openings in horizontal diaphragms with a dimension perpendicular to the joist that is greater than 4 feet (1219.2 mm) shall be constructed in accordance with LAMC Figure 91.5.503.2.4.
Figure 91.5.503.2.4
(Amended by Ord. No. 188,797, Eff. 12/31/25.)
[image omitted; see the official code]
a. Blockings shall be provided beyond headers.
b. Metal ties not less than 0.058 inch [1.47 mm (16 galvanized gage)] by 1.5 inches (38 mm) wide with eight 16d common nails on each side of the header-joist intersection. The metal ties shall have a minimum yield of 33,000 psi (227 MPa).
c. Openings in diaphragms shall be further limited in accordance with CRC Section R301.2.2.6.