Geotechnical engineer in San Francisco, California
San Francisco swings from solid Franciscan bedrock on the hills to some of the deepest, softest bay mud and artificial fill in the region — so the right foundation can change block to block.
The ground in San Francisco
The city's hills — Twin Peaks, Bernal, Nob Hill — are Franciscan sandstone, chert, and serpentinite, generally strong but sometimes steep. In contrast, SoMa, Mission Bay, and the Marina sit on deep Young Bay Mud and engineered or historic fill, where long-term settlement and downdrag on piles are major concerns. Understanding which regime your site is in is the first step.
Faults & seismic setting
San Francisco sits between the San Andreas and Hayward faults and saw dramatic, fill-related damage in the 1989 Loma Prieta earthquake, especially in the Marina. Liquefaction of loose fill and soft-ground amplification are the defining seismic issues for low-lying neighborhoods.
What we do in San Francisco
- Deep foundations and settlement analysis on bay mud in SoMa and Mission Bay
- Liquefaction evaluation in the Marina and along the waterfront
- Bedrock foundations and shoring on the hills
- Soft-story and seismic retrofit foundation support
- Excavation shoring and underpinning for basements
Areas we serve in San Francisco
- Marina
- SoMa
- Mission Bay
- Twin Peaks
- Bernal Heights
- Noe Valley
Permitting & review
Projects are reviewed by the San Francisco Department of Building Inspection (DBI), which has specific geotechnical requirements in mapped liquefaction and landslide zones. We prepare reports formatted to DBI's expectations.
Services for San Francisco projects
- Foundation EngineeringFoundation engineering follows the site investigation and precedes structural design. You need it for new construction, vertical additions that increase loads, and any project on soft, expansive, or filled ground where a generic footing detail would be a liability.
- Seismic HazardSeismic hazard assessment is required for essentially all new construction in the Bay Area and for many additions and retrofits. It is especially critical on bay mud, artificial fill, and near mapped fault zones, where liquefaction and lateral spread drive the design.
- Site InvestigationYou need a site investigation before design on any structure that transfers load to the ground — new buildings, additions, retaining walls, and hillside projects. Most Bay Area jurisdictions require a geotechnical report for permit submittal, and lenders increasingly ask for one before closing.
- Ground ImprovementGround improvement makes sense when shallow soils are weak or liquefiable but deep foundations would be costly — common on former industrial sites, engineered fill, and bay-margin parcels. We compare improvement against deep-foundation alternatives on cost and risk.
Geotechnical engineering in San Francisco — common questions
- Why do buildings settle on bay mud in SoMa and Mission Bay?
- Young Bay Mud is soft and compresses slowly under load for years. We measure its depth and strength with borings, then design deep foundations or ground improvement so your structure doesn't settle unevenly over time.
- Is liquefaction still a risk in the Marina after 1989?
- Yes — the loose, saturated fill that failed in 1989 is still there. For projects in mapped liquefaction zones, we quantify the hazard and design foundations, ground improvement, or deep piles to resist liquefaction settlement.
- Does SF DBI require a geotechnical report for my project?
- Frequently, especially in mapped seismic-hazard zones or for new construction, additions, and basements. We provide DBI-compliant investigations covering foundations, settlement, and seismic design.
Nearby service areas
Building in San Francisco? Let's talk about your site.
Send us the location and what you have planned. You'll get a straight answer on what the ground can carry — and a fixed-fee proposal within 24 hours.