A soft story building can look ordinary from the street. The risk is usually hidden in the first level.
Many older apartment buildings in California have parking, garages, storefronts, tuck-under spaces, or open walls at the ground floor. Those openings make daily life easier, but they can also make the first story weaker than the floors above. During an earthquake, that weak level can deform or collapse while the upper floors remain heavy and stiff.
That is why cities across California have adopted soft story retrofit programs. San Francisco has had a mandatory program for years. San Jose has adopted its own soft story retrofit ordinance and compliance program. Other cities and agencies are watching the same building type because the risk is well understood.
For apartment owners, the question is not just, “Do I have to comply?” The better question is, “What is the actual earthquake risk in this building, and what is the smartest way to reduce it?”
This guide explains what a soft story building is, why it matters, what owners should know about California retrofit requirements, and how a structural engineer evaluates retrofit options.
What is a soft story building?
A soft story building has one level that is significantly more flexible or weaker than the level above it. In California multifamily housing, this often means a wood-frame apartment building with open parking or garage spaces at the first story.
In practical terms, a soft story is a building level that cannot resist sideways earthquake movement as well as the floors above it. The weakness is often created by parking openings, garage doors, storefront glass, or limited wall length at the ground floor.
Common soft story conditions include:
- Tuck-under parking beneath apartments
- Garage doors along most of the ground floor
- Storefront glass or open commercial space at the first level
- Large openings with limited solid wall length
- A basement or underfloor area that extends above grade
- Older wood-frame construction built before modern seismic standards
The problem is lateral resistance. Earthquakes push buildings side to side. If the upper floors have more walls and stiffness than the first floor, the ground level can absorb too much of that movement. The result can be severe damage, unsafe evacuation conditions, or collapse.
Why soft story buildings are a known earthquake risk
Soft story buildings are not a theoretical concern. They have performed poorly in past earthquakes because the weak first story can become the failure point for the entire structure.
The Applied Technology Council describes multi-unit wood-frame buildings with weak first stories as a significant risk in highly seismic regions. FEMA P-807 was developed specifically to address seismic evaluation and retrofit of multi-unit wood-frame buildings with weak first stories.
California cities have focused on this building type because the risk combines three things:
- Life safety exposure. Multifamily buildings put many residents in one structure.
- Older construction. Many vulnerable buildings were designed before current seismic standards.
- Concentrated weakness. A single weak story can control the building’s earthquake performance.
For owners, the practical issue is clear. A soft story retrofit can reduce collapse risk, protect residents, preserve housing, and reduce post-earthquake disruption.
Who needs a soft story retrofit?
Requirements depend on the city and the building. Owners should always confirm applicability with the local building department, but most soft story programs focus on older wood-frame multifamily buildings.
A building may need screening if it has:
- Two or more stories
- Multiple dwelling units
- Wood-frame construction
- A ground floor with parking, garages, storefronts, or large openings
- Construction or permit dates before modern seismic code requirements
- A notice from the city requiring screening or evaluation
San Francisco’s mandatory soft story program applies to certain wood-frame structures with five or more residential units, two or more stories over a soft or weak story, and permits before January 1, 1978.
San Jose’s soft story retrofit program focuses on certain pre-1990 wood-frame multifamily buildings with a vulnerable target story. If you receive a city notice, treat it as the start of a screening and records-gathering process. Do not assume a building is exempt because it is small, occupied, or has stood for decades.
San Jose soft story retrofit ordinance: what owners should know
San Jose’s soft story retrofit program is especially important for South Bay apartment owners. The city has identified soft story buildings as a public safety and housing resilience issue, and the program gives owners a structured path for screening, design, permitting, and construction.
San Jose’s program groups subject buildings by age and unit count. The city’s criteria generally focus on older wood-frame multifamily buildings with two or more stories, three or more dwelling units, and a target story that may be vulnerable because of open parking, garage openings, or similar conditions.
Owners should verify current deadlines and screening instructions directly with the City of San Jose and any official notice they receive. Ordinance dates and compliance timelines can be updated, and the official city notice controls.
Miyamoto also maintains a San Jose seismic compliance resource for building owners: San Jose Seismic Compliance.
What happens during a soft story retrofit assessment?
A good retrofit starts with the building, not with a product. The engineer needs to understand the existing structure before recommending a solution.
A typical assessment may include:
- Document review. Existing drawings, permit records, prior retrofit work, unit layouts, and site constraints.
- Site observation. Verification of framing, wall lines, garage openings, deterioration, foundation conditions, and access.
- Screening or evaluation. Determination of whether the building is subject to a local ordinance and whether it meets required performance criteria.
- Structural analysis. Evaluation of the weak story and the load path from roof and floors into the foundation.
- Retrofit concept. Selection of practical strengthening measures that balance life safety, constructability, cost, tenant impact, and code requirements.
- Construction drawings and permitting. Documents for agency review and contractor pricing.
- Construction support. Responses to contractor questions, observations, and coordination during the work.
This sequence matters. Skipping the assessment can lead to expensive assumptions. A retrofit that works for one building may be wrong for another building across the street.
Common soft story retrofit methods
Soft story retrofit design depends on the building’s geometry, foundation, wall layout, parking needs, and local requirements. Common approaches include:
Steel moment frames
Steel moment frames are often used where the owner needs to preserve parking or garage openings. They can provide lateral resistance while keeping open bays usable. They are common in tuck-under parking conditions, but they require careful foundation and connection design.
Plywood shear walls
Plywood shear walls can strengthen existing wall lines where enough solid wall length is available. They are often cost-effective, but they may not work where openings dominate the first story.
Hold-downs and collectors
A retrofit is not only about adding new walls or frames. The load path matters. Hold-downs, collectors, diaphragms, and foundation anchorage help transfer earthquake forces through the structure.
Foundation upgrades
New lateral elements often need foundation work. This may include grade beams, footings, anchor bolts, or localized strengthening so new forces have somewhere to go.
Hybrid solutions
Many apartment retrofits use a combination of frames, shear walls, collectors, and foundation upgrades. The goal is not to overbuild. The goal is to deliver the required seismic performance with a solution that can actually be permitted and built.
How much does a soft story retrofit cost?
Costs vary widely. Building size, parking layout, foundation condition, tenant access, local labor markets, and permitting requirements all matter.
Owners should be cautious with generic estimates. A small building with simple wall lines may be very different from a larger apartment building with continuous garage openings and poor foundation conditions.
Early engineering helps owners make better financial decisions because it can identify:
- Whether the building is likely subject to an ordinance
- Whether an exemption or screening path may apply
- The likely retrofit scope
- Cost drivers before contractor pricing
- Tenant and access constraints
- Phasing issues
- Grant or incentive timing concerns
For some residential owners, California programs such as Earthquake Brace + Bolt and Earthquake Soft-Story may provide financial assistance when eligibility requirements are met. These programs are not a substitute for project-specific engineering, and owners should verify current eligibility before starting construction.
Why owners should not wait until the deadline
Retrofit deadlines can create a false sense of time. A deadline several years away may seem distant, but the process can move slowly once every owner in a city starts seeking engineers, contractors, and permits.
Waiting can create four problems:
- Limited engineering availability. Demand rises as deadlines approach.
- Higher construction pricing. Contractors get busier near compliance dates.
- Permit bottlenecks. Agencies may see large waves of similar submittals.
- Fewer design options. Rushed projects leave less time to compare approaches.
Early evaluation does not always mean immediate construction. It gives owners information. That information helps with capital planning, refinancing, insurance conversations, tenant communication, and long-term asset strategy.
Soft story retrofit and affordable housing
Soft story risk is also a housing preservation issue. Many vulnerable buildings are older apartments that provide naturally affordable or publicly supported housing. If those buildings are damaged in an earthquake, residents can be displaced and communities can lose critical housing stock.
Miyamoto International’s work with the San Diego Housing Commission Seismic Retrofit Program shows how seismic retrofit can support housing resilience. Miyamoto provided structural engineering services for 11 existing two-story wood-frame buildings on 10 properties throughout San Diego. The team performed condition assessments, observed deterioration, took measurements, analyzed the buildings, developed construction drawings for seismic upgrades, and supported the project during bidding and construction.
That kind of work is not just about code compliance. It is about keeping housing usable after a seismic event.
What property owners should do next
If you own or manage an older apartment building with tuck-under parking, garages, storefront openings, or an open first story, start with a practical screening conversation.
Gather:
- Building address
- Year built or permit date
- Number of stories
- Number of dwelling units
- Existing drawings, if available
- Photos of the ground floor and parking areas
- Any city notice or screening instructions
- Prior retrofit or repair records
Then ask a structural engineer three questions:
- Is the building likely subject to a local soft story ordinance?
- What information is needed to confirm the risk and compliance path?
- What are the likely retrofit options, cost drivers, and schedule risks?
The best time to answer those questions is before the deadline pressure starts.
Work with Miyamoto International
Miyamoto International provides structural engineering and seismic resilience expertise for building owners, public agencies, housing providers, and communities. Our work includes earthquake assessment, seismic retrofit, affordable housing resilience, and post-disaster recovery.
If you own or manage a potentially vulnerable apartment building, Miyamoto can help evaluate the risk, develop a retrofit strategy, and support the process from assessment through construction.
Contact Miyamoto International to discuss a soft story retrofit assessment for your building.
Requirements vary by jurisdiction. Owners should verify official notices and current program requirements with the local building department.
Frequently asked questions
What does “soft story” mean?
A soft story is a level of a building that is significantly weaker or more flexible than the floors above it. In California apartment buildings, this often happens at the ground floor where parking, garages, or storefronts reduce the amount of solid wall.
Are all older apartment buildings soft story buildings?
No. A building’s age alone does not prove that it has a soft story condition. Age, framing type, wall layout, openings, and local ordinance criteria all matter. Screening or engineering evaluation is the right first step.
Does San Jose have a soft story retrofit ordinance?
Yes. San Jose has adopted a soft story retrofit ordinance and program for certain older multifamily buildings. Owners should check the city’s current program page and any official notice for the screening, design, permit, and construction deadlines that apply to their building.
What is FEMA P-807?
FEMA P-807 is a guideline for seismic evaluation and retrofit of multi-unit wood-frame buildings with weak first stories. It was developed to address the collapse risk associated with this common building type in high seismic regions.
Can a retrofit preserve parking?
Often, yes. Many retrofit designs use steel moment frames or other targeted structural elements to improve seismic performance while preserving useful openings. The right solution depends on the building.
How early should owners start?
Owners should start as soon as they know or suspect a building may be subject to an ordinance. Early screening helps avoid deadline pressure, contractor bottlenecks, and rushed design decisions.
