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  • Writer's pictureMike Abell, Professional Civil Engineer

How much does Soft-Story Retrofit cost?


"Soft-story" buildings have a level with less strength and stiffness than the levels above. This occurs with an open-plan ground floor that serves as a garage, storage, or crawl space. Here, the ground floor often has less strength and stiffness than the occupiable levels above because the habitable spaces have many interior walls that provide strength and stiffness. Most older multi-unit residential buildings and single-family homes are soft-story buildings.

Soft-Story Retrofit

Unfortunately, these buildings are vulnerable to collapse during a major earthquake. That's why "soft-story retrofit" is important to strengthen the soft story and mitigate seismic risk.

Voluntary Soft-Story Retrofit

Those who own a soft-story building in a seismic region should take initiative and retrofit their building. A retrofit can significantly reduce the risk of collapse, reduce the amount of damage, and improve the likelihood that tenants can stay in the building. Repairs and vacancies are costly. It's better to pay money up front to retrofit the building than to pay later when the building is damaged and possibly vacant. Additionally, a retrofit may save litigation in the event of death or injury.

Earthquake Insurance

It's worth noting that money is better spent on an actual retrofit than on earthquake insurance. Take precautions and retrofit your building so that you don't have to rely on earthquake insurance when your building is damaged, vacant, and no longer provides cash flow.

Mandatory Soft-Story Retrofit

Given the seismic risk in earthquake-prone regions, many cities are launching mandatory soft-story retrofit programs that require the retrofit of certain types of vulnerable buildings. These buildings tend to be older, wood-frame, multi-unit, soft-story buildings that are higher in population density and have relatively straightforward retrofit solutions. Cities implement mandatory soft-story retrofit programs to mitigate disaster, promote seismic resilience, retain their population, and enhance recovery.

A few resources for the Oakland Mandatory Soft-Story Retrofit Program include:

Retrofit Cost

The cost for a soft-story retrofit depends largely on the size of the building and the layout of the soft story, which is commonly the ground floor. The most economical type of retrofit uses only wood-frame shear walls installed into existing concrete foundation footings.

  • Typical 5- to 12-unit buildings should cost $60,000 to $80,000.

  • Smaller multi-unit buildings and single-family homes should cost $30,000 to $50,000.

  • Larger multi-unit buildings should cost $90,000 to $120,000.

However, the price may be driven higher when the sides of a building don't have enough length of solid wall to meet code requirements with only wood-frame shear walls. In this case, more costly seismic systems (such as steel moment framing) must be installed around such openings as garage doors, windows, and entryways.


Cities that mandate retrofit often coordinate financing programs with lenders. Check your city's website for details.

Capital Improvement

Soft-story retrofit is a capital-improvement cost that is tax-deductible. Further, cities let property owners recapture costs through rent increase. Oakland, for example, lets owners recapture 70% of all costs with 10% rent increase over 25 years. Their FAQ Page (items 14 and 15) describe how to submit the Petition Form to the Rent Adjustment Program.


Be aware of your deadlines for mandatory retrofit. The first deadline is to determine whether or not your building belongs in the program. All possible buildings are screened into the program. If your building does not meet the criteria of the program, a licensed design professional can exempt your building so that retrofit is not required. If retrofit is required for your building, the second deadline is for submission of your permit application. The final deadline is then for completion of construction.

Hire an Engineer

To begin your soft-story retrofit project, start by talking to a few engineers. You may want to speak with two or three engineers to see if there's consistency in what they're saying, as there are different ways to design a retrofit, and each engineer may have unique perspective and insight.

Engineering design fees can range anywhere from $5,000 to $20,000, depending on the scope and complexity of the project. Gather a few quotes and review your options. When deciding which engineer to hire, don't necessarily go with the lowest quote. Consider the engineer's experience and value, which can save you money during construction and result in a superior outcome.

Additional Dwelling Unit

Since a soft-story retrofit strengthens the existing configuration of a building without altering the floor plan, an architect is typically not involved in the process. However, if you're considering adding one or more additional dwelling units (ADUs) to your building, you will need an architect and an architectural submission to the city. In this case, the architect and engineer can work together to design the ADU within the layout of the retrofit.

As-Built Drawings

Once you hire an engineer, they will need "as-built drawings" that show the existing architectural layout of each building level. As-built drawings can be developed by a third party who will visit your property, collect measurements, then draw the floor plans in CAD format. We recommend Precision Property Measurements (PPM) for this service, which should cost around $3,000, depending on the square footage of your building.

Engineering Design

The engineer will then use these as-built drawings to design your retrofit. The permit submission will include structural plans and a report that demonstrates compliance with building code. This process should take two to three weeks, depending on the complexity of the project.

When design is complete, the engineer will provide you with PDF files for the structural plans and report. These documents are submitted to the city with a permit application when you're ready to move forward with the permit application process.

Building Permit

The city's building department will then review the material and either approve the project for construction or issue comments for correction. If comments are issued, the engineer will address them and resubmit for plan check. Once the permit is approved, you can hire a contractor and move forward with construction. Permit fees are usually around $3,000, and due either at the start or conclusion of plan review.

Hire a Contractor

Have a few contractors review the project and provide you with a quote for construction. Remember, don't necessarily go with the lowest quote. Some professionals price a bit higher because they are more skilled and resourceful, have more experience, and add more value to your project. You may be better served by paying a slight premium for more qualified specialists.

During Construction

During the initial stages of construction, it's important to meet the superintendent, also known as the "super" or the "foreman." This individual is the construction manager who will be working on your project full time, managing the crew and the work. Feel free to periodically check on progress, have the superintendent show you around, and ask them questions.

Special Inspection

During construction, the contractor will coordinate special inspections. A building official from the city will visit the site at key junctures to check the work that is being done, and certify that completed work follows the approved plans and building code.

After Construction

As soon as work is complete, take a look around your project. Let the contractor or superintendent know of any issues that may still be outstanding. Make sure everything is clean and finished to your satisfaction. Then... congratulations, your project is complete!

Planning a Soft-Story Retrofit?

We at City Structural, Inc. specialize in soft-story retrofit. Our team of experienced professionals can help you with your project from start to finish. Leave us a message below in our website footer, and we'll be happy to provide you with a complimentary briefing on your building and project. We look forward to helping you get started.

Oakland soft story retrofit program structural engineering construction project residential building photo

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