An engineering report assessing soil bearing capacity, expansive-soil risk, and foundation recommendations for a specific lot.
Required by many California cities for ADU permits, particularly for hillside, expansive-clay, or seismic-fault-zone properties. Cost: $2k-$8k. Findings can require engineered foundations, drainage systems, or even site-redesign — discovered late, this is a major project delay.
Part of the BackyardADU California ADU Glossary — plain-English definitions of the regulatory, construction, and financing terms you'll encounter during a California ADU project.