Yerba Buena completed the design-build installation of a new foundation under a historic building on the shore of San Francisco Bay. The new, higher foundation was to meet current seismic standards and provide required clearance between the untreated wood building and the ground below.
We took the highest level of care to preserve and protect the building’s historic fabric. We also prepared and implemented a plan to prevent accidental contamination of the adjacent bay.
We removed the wood decks and brick patios, removed the building siding to expose joists and beams, and excavated to expose the foundation. Then we shored the building’s interior and jacked the building up to 6 feet 8 inches off the ground.
We jackhammered out the old footing and foundation, formed and poured new ones, replaced a sewer line, laid down a moisture barrier, and poured a concrete rat slab in the crawl space. Around the foundation we saw cut 70 feet of asphalt to put in a French drain.
On the building’s underside, we found extensive wood rot. The building had to be lowered to 4 feet above the foundation so workers could safely complete the rot repairs. Then the building was lowered onto the new foundation.
We modified the hardscape and replaced, primed, and painted the siding. Inside, we replaced the lavatory plumbing and the damaged drywall.
We overcame several challenges on this project, including heavy rains, and waves cresting the seawall and flooding the foundation trenches.
- Project Name: Design Build Foundation for Building 989, Fort Point National Historical Site
- Category: Other Projects
- Client/Owner: National Park Service
- Location: San Francisco, CA
- Dollar Amount: $435,045
- Lead-based paint stabilization
- Building lifting and lowering
- Concrete demolition
- Concrete foundation installation
- Wood rot repair
- Tree removal and hardscape repairs
- Sewer line replacement
- Asphalt saw cutting
- French drain installation
- Drywall repair