The purpose of this Information Bulletin is to summarize the procedure determining soil bearing capacity for foundation design of a single family, duplex, townhome 3-stories or less in height, and for their accessory structures. When submittal of a geotechnical investigation report is not required per the San Diego Municipal Code (SDMC) Section §145.1803, the foundation design shall be based on the presumptive load-bearing capacity in accordance with the current California Residential Code (CRC). 

Fill Material

A preliminary geotechnical report or as-graded geotechnical report prepared by a registered design professional shall be submitted with all plans for buildings and structures supported on fill material. The preliminary geotechnical report or graded geotechnical report shall be prepared in accordance with the City’s Guidelines for Geotechnical Reports. 

Expansive Soil

A preliminary geotechnical report or as-graded geotechnical report prepared by a registered design professional shall be submitted with all plans for buildings and structures supported on expansive soil as described in Section R202 of the 2022 CRC. The preliminary geotechnical report or as-graded geotechnical report shall be prepared in accordance with the City’s Guidelines for Geotechnical Reports.

Notes on Plans

1. When the site soil condition is not an expansive soil or fill material, the foundation may be designed for the presumptive load-bearing capacity of 1,500 pound per square foot and the following note shall be placed on plans:

“The undersigned acknowledges by their signature below that the presumptive load-bearing capacity of 1,500 pounds per square foot is assigned for foundation where the foundation is embedded in non-expansive natural ground. The undersigned understands that if the building inspector observes or suspects that fill materials or expansive soils are present in the building area, a geotechnical report prepared by a California registered design professional may be required.”

Designer/owner                                                              Date signed                                                                             

2. Alternatively, the foundation design shall be based on the 2022 CRC, Section R401.4 and Table R401.4.1. The foundation plan must indicate the class of the foundation bearing material and presumptive load-bearing values and must be signed by a civil engineer or architect licensed by the State of California.  The following note shall be placed on the foundation plan:

“As a California licensed engineer/architect, I have classified the natural ground materials as _____________   per Table R401.4.1 of the current California Residential Code, and assigned a load-bearing capacity of __________ pounds per square foot for design of foundations related to this project. “ 

Engineer/Architect                                                              Date signed                                                                         

References

• San Diego Municipal Code: Geotechnical Investigations Section §145.1803
• Guidelines for Geotechnical Reports 
• 2022 California Residential Code (CRC)

Previous Versions of this Information Bulletin

This section contains previous versions of this Information Bulletin by the last day they were effective. 

• 2024-11-06 | IB-141