What Is a Soft-Story Building and Earthquake Risk in San Jose 2025?

Quick Answer: A soft-story building has a first floor (or “story”) that is significantly weaker or more flexible than the floors above it — typically caused by large openings in the ground floor (tuck-under parking, storefronts, or large windows) that replace the solid walls that would otherwise resist lateral earthquake forces. In the 1989 Loma Prieta earthquake, soft-story apartment buildings across San Jose and the Bay Area collapsed or pancaked on their ground floors while the upper stories remained intact. San Jose has a mandatory soft-story retrofit ordinance requiring multi-unit residential buildings (2+ units) built under pre-1978 codes with a soft-story condition to be retrofitted by specified deadlines. For single-family homes, the “soft story” concern is usually a garage or crawlspace under a living area — a cripple wall retrofit ($3,000-$10,000) strengthens this condition.

Soft-Story and Earthquake Retrofit Guide for San Jose Homes

• What makes a ground floor “soft”: Any first-floor wall line that has a ratio of opening (doors, windows, garage openings) to total wall length exceeding approximately 50% on any wall face, combined with stories of wood-frame construction above. Open-front garage buildings and retail-to-apartments mixed-use are the classic examples
• Cripple wall retrofits (single-family homes): The most common residential earthquake retrofit in San Jose. The cripple wall is the short wood-framed wall between the foundation and the first floor in a raised-foundation home. Without blocking and sheathing, cripple walls can collapse sideways in an earthquake. The retrofits add plywood sheathing, anchor bolts, and mudsill connections at approximately $3,000-$10,000 for a typical single-family home
• IBSS (Instilled Bolt Shear Specimens) programs: FEMA’s Brace + Bolt program offers grant funding for cripple wall retrofits in qualifying homes. Apply at earthquakebraceandbolt.com for California homeowner grants up to $3,000 toward a qualifying retrofit
• San Jose mandatory screening: The City of San Jose has an inventory of pre-1978 multi-unit residential buildings that require engineering evaluation. Single-family homes are not subject to mandatory retrofit orders, but are encouraged to voluntarily retrofit
• Cost of multi-unit soft-story retrofit: A typical 8-unit tuck-under apartment building soft-story retrofit costs $80,000-$200,000 depending on the required scope. Engineers design steel moment frames, plywood shear walls, or a combination to add lateral resistance to the ground floor

Quartz Construction performs residential earthquake retrofits including cripple wall strengthening, anchor bolt installation, and foundation connections throughout San Jose. Learn about foundation and seismic retrofit services. CSLB #1003436 | Call (650) 749-7436.

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Quartz Construction & Remodeling | CSLB #1003436 | Licensed, Bonded & Insured

Phone: (650) 749-7436

Address: 1777 Hamilton Ave #1080, San Jose, CA 95125

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Service Area: San Jose, Santa Clara, Sunnyvale, Mountain View, Los Gatos & Bay Area