If your building has parking, storage, or open space underneath the living units, it likely has a soft story. In an earthquake, that open first floor is the part that collapses. Here is what that means and what fixing it involves.
A soft story is a floor of a building that is significantly weaker than the floors above it. In residential buildings, this almost always means the ground floor has been opened up for something useful: parking, a garage, a storefront, or a tuck-under carport.
The problem is structural. Walls are what resist side-to-side shaking in a wood-frame building. When you remove most of the ground-floor walls to fit cars underneath, you remove most of the ground floor's ability to resist that shaking. The upper floors stay stiff and heavy. The bottom floor does not.
You can usually spot one from the street. Look for:
In an earthquake, a soft story can fail while the rest of the building stays intact. The upper floors drop straight down onto the collapsed first floor. This pattern caused significant residential losses in California earthquakes and is the reason cities now require these buildings to be retrofitted.
The goal is to give the first story back the strength it lost. Depending on what the structural engineer's analysis calls for, that work includes some combination of:
Most of these jobs also involve utility relocation, since gas lines, electrical panels, and plumbing are frequently mounted right where a new frame needs to go.
| Step | What happens | Who does it |
|---|---|---|
| 1. Screening | An engineer evaluates whether the building has a soft-story condition and files the required report with the city. | Structural engineer |
| 2. Design | Full retrofit design to the applicable standard, producing stamped drawings. | Structural engineer |
| 3. Permit | Drawings submitted for plan check and permit issuance. | Stage 5 coordinates |
| 4. Construction | Shoring, demolition, steel and framing installation, foundation work, finishes. | Stage 5 |
| 5. Inspection | City inspections plus special inspection for welding and anchors. | City + special inspector |
| 6. Sign-off | Final approval and compliance filing with the city. | Stage 5 coordinates |
No contractor can give you a firm construction price before step 2 is done. The cost depends almost entirely on how many steel frames the engineer's design calls for, and nobody knows that number until the analysis is complete. Be cautious of anyone who quotes a hard number before there are stamped drawings.
Soft-story requirements are not limited to any one building size. San Jose's ordinance applies to wood-frame buildings with three or more units. We work on buildings from three units up through twenty and above.
Separately, the state EMR (Earthquake Multi-Unit Retrofit) grant program applies specifically to buildings with five to ten units. If your building falls in that range you may be eligible for funding, but the retrofit requirement applies either way.
Send us the address and unit count. We will tell you straight whether it looks like a soft-story condition and what your city requires.