SEC. 91.1803. GEOTECHNICAL INVESTIGATION.
Los Angeles Rent Rules (LAMC excerpts) · 2025 edition · ingested 2026-07-08 · Los Angeles
(Amended by Ord. No. 185,587, Eff. 7/16/18.)
Section 1803 of the CBC is adopted by reference, except Section 1803.5.6 of the CBC is not adopted; and, in lieu, LAMC Subdivision 91.1803.5.6 is added.
91.1803.5.6. Rock Strata. Where subsurface explorations at the project site indicate variations or doubtful characteristics in the structure of the rock upon which foundations are to be constructed, a sufficient number of borings shall be made to a depth of not less than 10 feet (3048 mm) below the level of the foundations and to a depth that would allow investigation of any unsupported bedding planes or any other rock discontinuities that could influence the foundation stability to provide assurance of the soundness of the foundation bed and its load-bearing capacity.