Foundation bolting, cripple wall bracing, hold-downs and engineered shear walls. Leafair builds what your structural engineer specifies, and coordinates the permit and inspections.
In an earthquake, a house that is not properly tied together tends to fail where its parts meet — the frame slides off the foundation, the cripple walls in the crawl space rack over, the ground floor of a building with a wide garage opening deflects while the floors above keep moving.
A retrofit addresses those connections. It is not about making a house stronger everywhere; it is about making sure the load path from roof to foundation is continuous and that the weak points have been identified and braced.
Anchor bolts or plates tying the mudsill to the concrete foundation so the framing cannot slide off it.
Structural sheathing applied to the short walls between the foundation and the first floor, which are a common failure point in older homes.
Steel hardware resisting the uplift forces that try to lift a braced wall off its footing.
Engineered wall panels that carry lateral load. Where these land in finished space, the room is opened and made good afterwards.
Buildings with a wide garage opening or open ground floor beneath living space need a specific engineered solution, often steel moment frames.
Rot, previous alterations and undersized members found during the work have to be corrected before the new structure is attached to them.
A structural engineer assesses the building, determines what is required, and produces stamped drawings and calculations. That is their work, not a contractor’s, and Leafair does not present itself as qualified to do it.
Leafair’s role is construction: opening up the work areas, building exactly what the drawings specify, coordinating inspections and making good afterwards. Where hardware or fastening patterns differ from the drawings on site, the engineer is consulted rather than the detail being improvised.
Engineering assessment and drawings. Permit. Access — clearing crawl spaces or garages so the work areas can be reached. Demolition and opening up where shear walls are going in. Structural work: bolting, bracing, hold-downs, framing repairs. Inspection. Close-up and making good.
Cost is driven mostly by access, by how much finished space has to be opened, by what is found in the existing framing once it is exposed, and by whether the solution is prescriptive bracing or an engineered frame.
Read the San Francisco seismic retrofit guide for a fuller walk-through. For foundation replacement, underpinning and retaining walls see foundations and structural work, and see the completed foundation and retaining wall project.
It is structural work that improves how a building resists earthquake forces — typically by connecting the house properly to its foundation, adding bracing to weak walls, and tying the framing together so the structure moves as one unit instead of coming apart at the joints.
Older San Francisco homes, particularly those built before modern seismic codes and those with living space over a garage or open ground floor, are the ones most often identified as candidates. Whether yours needs work is a question for a structural engineer, not a contractor.
For anything beyond the simplest prescriptive work, yes. Leafair is a licensed general contractor and builds what the engineer specifies — it does not design the structural solution or issue the calculations. You will be referred to engineers Leafair works with regularly.
Structural work of this kind is permitted work and is inspected. Leafair coordinates the permit and holds the job at each inspection point rather than covering work that has not been signed off.
Much of it happens in the crawl space, garage or at the ground floor perimeter, so many households stay in the property throughout. Where shear walls go into finished rooms, those areas are opened, worked and made good.
Leafair will walk the site, talk through what is realistic, and give you a written estimate priced line by line. Estimates are free.
