What is a soft-story building?

A soft-story building has a ground floor that is significantly more open than the floors above it, usually because of parking, retail, or large windows replacing what would otherwise be structural infill walls. That open ground floor concentrates seismic stress in a single, weaker level, and is a well-documented collapse mechanism in wood-frame multi-unit buildings during earthquakes.

How many San Francisco buildings are still non-compliant with the soft-story ordinance?

As of the current San Francisco Department of Building Inspection data Tessera ingests, 261 buildings on the Mandatory Soft Story Retrofit Program list are still marked non-compliant, out of roughly 4,900 buildings the program has ever identified. Most of the list, over 4,580 buildings, already shows a completed retrofit with a Certificate of Final Completion issued.

San Francisco's Mandatory Soft Story Program, mapped to every building

San Francisco already did the hard part: identifying which buildings have the single most-cited wood-frame collapse mechanism in a major earthquake. That list is real, public, and building-specific. Here's what it says, and how it changes a retrofit score when the input is the city's own determination instead of an inference from tags.

Most cities Tessera scores don't have anything like this. Istanbul's retrofit priority infers a soft-story risk from OpenStreetMap typology tags, a real but indirect signal: a building tagged "Mixed Use," meaning ground-floor retail under residential floors above, is a plausible but not confirmed soft story. San Francisco's Department of Building Inspection has already done the confirmation, building by building, under a real regulatory program: the Mandatory Soft Story Retrofit Program, which requires owners of wood-frame buildings with five or more units, two or more stories, and a permit predating 1978 to seismically retrofit the ground floor.

Why the ground floor specifically

The 1989 Loma Prieta earthquake is the reference event for this ordinance, and San Francisco's own Marina District is the reference damage: multi-unit wood-frame buildings with open, garage-lined ground floors pancaked at that level while the residential floors above stayed largely intact until they came down with it. The mechanism is structural, not anecdotal: a ground floor with large openings for parking or storefronts has far less lateral stiffness than the floors above, so seismic force concentrates there instead of distributing through the building. It's the same failure mode FEMA's P-154 Rapid Visual Screening methodology scores as a distinct, named irregularity, not a subset of general building age.

Buildings on the SF list~4,900

Still non-compliant261

Work complete, CFC issued4,588

That's a real compliance rate above 93%, which is itself worth stating plainly: this ordinance mostly worked. The 261 buildings still open are the ones a retrofit-priority score should actually be pointing at, not the whole historical list undifferentiated. Tessera's San Francisco layer makes exactly that distinction: only the still-non-compliant subset feeds a real +8 point bonus into retrofit_score, the largest single bonus in the entire scoring model, deliberately larger than every geometry-only proxy it also computes (adjacent-building pounding risk, plan irregularity, corner exposure), because this one input is a government engineering determination, not an inference from footprint shape or OpenStreetMap tags.

What this changes in the score

Across San Francisco's 177,023 mapped buildings, retrofit priority currently classifies as:

Retrofit-priority classification across San Francisco's mapped buildings.

The soft-story bonus is one input into that base score, not the whole of it; San Francisco's own real ground-shaking scenario and each building's real code-era risk (from the city Assessor's own year-built records) carry more of the weight, because they apply to every building, not just the ~4,900 on this one list. But for the 261 buildings still flagged non-compliant, it's the single most confident signal Tessera has anywhere in its current city coverage: a real regulatory finding, not a statistical pattern.

See how any specific San Francisco building scores on the live map, or read what the underlying Hayward Fault scenario means for the hazard side of the same score.