Regulations on Building Permits & Concrete Foundations in California

Foundation and Soils Investigations

• A soils report is required in the building code for proposed construction, prepared by a registered engineer. The engineer will determine if further testing is needed, such as a geologic and earthquake report, geotechnical report or in-ground response. The building official may waive the soils report requirement if enough information is available from adjacent sites, but if the site is located in Seismic Design Category D, E or F, no exception will be made.

Foundation

• A number of requirements for foundation design to withstand seismic activity are outlined in the building code and must be complied with if the site is in a seismic zone. The initial site investigation identifies concerns and the extent of the involvement of an engineer for the design of the foundation An engineer may have to stamp the house plans, and a site inspector may have to be present during the work.

Damp-proofing and Waterproofing

• Waterproofing keeps liquid water away from the foundation, and damp-proofing keeps away moisture in the soil that can create high humidity levels, mold growth and rot. The California Building Code requires an approved drainage system to be installed for exterior below-grade parts of the foundation, or where it retains earth. It can drain by gravity or by mechanical means. The grading requirement helps keep surface water from accumulating near the foundation.

Grading

• The ground adjacent to the building has to be sloped at 5 percent away from the building, dropping 5 inches for every 10 feet. This helps prevent moisture from accumulating near the foundation and undermining soil stability. Adjacent paved surfaces must slope at 2 percent, or 2 inches for every 10 feet. Where the minimum slope can't be met, drains or swales must be installed. The final level of the grade has to take into account any settlement of the material.