Mike Abell, Professional Civil Engineer
What property owners should know about their soft-story retrofit
What is a "Soft Story"?
A "soft story" is when a building level has less strength and stiffness than the level above. A building with this condition is considered a "soft-story building."
This typically occurs in older multi-unit residential buildings and single-family homes that have a ground floor that is open in plan due to garage, storage, or crawl spaces. 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.
What is a Soft-Story Retrofit?
These soft-story buildings are vulnerable to collapse during a major earthquake.
A “soft-story retrofit" is when the soft story is structurally strengthened to mitigate this seismic risk.
Voluntary Soft-Story Retrofit
Those who own a soft-story building in a seismic region should take initiative and retrofit their building.
After a major earthquake, a retrofit will:
- Reduce the risk of collapse
- Reduce the amount of damage
- Improve the likelihood that your 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.
A retrofit may also save litigation in the event death or injury.
This goes for earthquake insurance as well. 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
Because seismic risk is such a concern to 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 straight-forward retrofit solutions. This way, the mandatory soft-story retrofit program can optimize for the most people, the most cost effectively.
When a major earthquake strikes within or near a major metropolitan area, it can be an extraordinarily costly national disaster that ruins the local economy for a long time. Buildings collapse, damage is extensive, populations are displaced, and relief funds aren't sufficient to offset the many costs.
Cities implement mandatory soft-story retrofit programs to mitigate disaster, promote seismic resilience, retain their population, and enhance recovery.
The Oakland Soft-Story Retrofit Program is one such effort. A few resources include:
- Oakland Soft-Story Retrofit Program Website
- Oakland Soft-Story Retrofit Program FAQ Page
- Oakland Soft-Story Retrofit Building Code
How Much Will My Soft-Story 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. You need enough length of solid wall (wall without openings) along each side of the building to accomplish this type of retrofit, which should cost $20,000 to $60,000 for smaller buildings, and $60,000 to $120,000 for larger buildings.
The price is 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. This is the case when a building has many openings along one or more sides, such as with garage doors, entryways, and windows.
Along these sides of the building, steel moment frames or other proprietary products must be installed around the openings. This requires new foundation footings to anchor these systems.
Each steel moment frame should add $20,000 to $30,000 to the pricing previously mentioned.
Financing for Mandatory Soft-Story Retrofit
Cities with a mandatory soft-story retrofit program often coordinate generous financing programs with lenders.
A good place to start looking for financing options is the city website for the mandatory soft-story retrofit program.
A soft-story retrofit is a capital-improvement cost that is tax deductible.
Cities with mandatory soft-story retrofit programs often let property owners recapture most or all the retrofit cost through a nominal rent increase over a time period.
The Oakland Soft-Story Retrofit Program lets property owners recapture up to 70% of all retrofit costs, including design and permit fees, with a 10% rent increase over 25 years. More information is available on the Oakland Soft-Story Retrofit Program FAQ Page under Items 14 and 15, which include the procedure for cost pass-through and how to petition the Oakland Rent Adjustment Program with the Property Owner Petition Form for Approval of Rent Increase.
Deadlines for Mandatory Soft-Story Retrofit
If your city requires the retrofit of you building, be aware of deadlines. There should be an initial deadline for determining whether your building belongs in the program. If your building does not meet the criteria of the program, an engineer or another licensed design professional can exempt your building from the program so you aren't required to retrofit.
If a retrofit is required, the next deadline is for the completion of the engineering design and submission of the permit application to the city. This deadline is typically two years from the initial deadline.
The final deadline is for when construction needs to be completed. This is typically another two years from the permit application submission deadline.
Deadlines for the Oakland Soft-Story Retrofit Program are listed on the Oakland Soft-Story Retrofit Program FAQ Page under Item 7. The compliance tier for your building should be listed on the top of your Notice of Mandatory Seismic Retrofit sent by the City of Oakland in May 2019.
Meet with Engineers
To begin the process, talk with a few engineers. They'll be happy to discuss your project and answer questions.
You may want to talk with two or three engineers to see if there's consistency in what they're saying. There are sometimes different ways to design a retrofit. Each engineer may have unique perspective and insight.
Gather Engineering Quotes
Engineering design fees can range anywhere from $5,000 to $20,000, depending on the scope and complexity of the retrofit.
Gather a few quotes to review your options.
Hire an Engineer
When deciding which engineer to hire, don't necessarily go with the lowest quote. Many engineers provide additional value and experience that can save you money with the economy of their design and value added during the construction process.
You'll also likely get a superior outcome with a more experienced engineer who understands the nuance of design, permitting, and construction. There are many design and construction details you'll want accounted for when an earthquake occurs.
No Architect is Required
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.
Additional Dwelling Unit (ADU)
However, there are things you can do concurrently with your soft-story retrofit, such as converting your ground floor into habitable space with one or more additional dwelling units (ADUs). This does require an architect and an architectural submission to the city.
If you'd like to explore your options for an ADU, meet with a few architects and contractors as well. The engineer can give you a sense of the retrofit scope, then the ADU can be designed within the layout of the retrofit.
Once you hire an engineer, they can get started when they have "as-built drawings." These are drawings that show the existing architectural layout of each building level.
When a retrofit is designed and submitted for permitting, the entire building must be shown in the plan set, including the floor plan for each building level.
Hopefully, you already have these drawings in CAD format so they can be imported into CAD software and used as a backdrop for engineering design.
If you don't have as-built drawings in CAD format, but do have them printed on paper, you can take these hard copies to a copy shop and have them scanned into PDF format. Then a drafter can import the PDF into CAD software and trace the architectural layout into CAD format.
If you do this, be sure to get both the PDF and CAD files of your building and retain them for your records. These are a great resource, as they’re required any time you submit a permit application for a building project.
If you don't have CAD files or hard copies of your as-built plans, they can be developed by a third party who will visit your property, collect measurements, then draw the layout of each level. This should cost around $3,000, depending on the square footage of your building.
We typically recommend Precision Property Measurements (PPM). They perform excellent work, price cost-effectively, and provide photos that are useful for design, and for your records.
The engineer will then design your retrofit using these as-built drawings as the backdrop. The design will include:
- Plan views that show where the structural elements occur within your building
- Structural details that specify how these elements and systems connect
- A report that demonstrates compliance with the building code
The engineering design should take two to three weeks, depending on the complexity of the project.
CEBC A4 Building Code
Most engineers use the CEBC A4 building code, which has long been the standard.
This building code provides a conservative design that is relatively extensive in scope.
FEMA P-807 Building Code
FEMA P-807 is a newer building code created by the Applied Technology Council in 2012 for implementation in San Francisco's mandatory soft-story retrofit program. This building code is more analytically comprehensive than CEBC A4, and it provides for a more economical retrofit.
FEMA P-807 credits the existing capacity of wall sheathing assemblies that already exist throughout the building, whereas CEBC A4 ignores the existing structure and only considers the strength of the retrofit in meeting seismic demand.
One can argue, then, that FEMA P-807 enables a more realistic and rigorous assessment of seismic performance. Enhanced by torsional and other analytical applications not considered with CEBC A4, the output is a less extensive retrofit that still complies with building code.
Some jurisdictions don't adopt FEMA P-807 into their building code, though they may still approve such a retrofit if submitted for permitting.
There are some technical limitations, as described in the Structure Magazine article FEMA P-807 for Soft-Story Retrofits by Bruce F. Maison, S.E.
There are constraints associated with the use of FEMA P-807 in that some buildings don't qualify.
If you're interested in minimizing the cost of your retrofit while meeting code requirements, hire an engineer proficient in FEMA P-807. As mentioned, most engineers don't use this building code because it's a lot of work to learn and apply new methods. But if you find someone, it could result in significant savings during construction.
Engineering Design Complete
When the design is complete, the engineer will let you know.
Be sure to receive a PDF of the plan set. Much of this information may seem foreign, but feel free to take a look and ask any questions that you may have.
When you're satisfied with the design, let the engineer know they can submit to the city for plan review. Since the engineer knows the process, this will be much easier than doing it yourself.
The Permit Process
At this point, a permit application is filled out and submitted to the city with the structural document set (that shows the retrofit design) and the engineering design report (that demonstrates compliance with building code).
The city's building department will then review the material and either issue comments to the engineer or approve the project for construction.
If comments are issued, the engineer will address the comments, integrate these revisions into the design, and then resubmit for plan review. This should be included in your initial fee, so don't pay extra for the engineer to address plan check comments.
This process should take four to eight weeks. Once the permit application is approved, you can hire a contractor and move forward to construction.
Permit Application Fee
A permit application fee will be applied at some point during this process, either when the permit application is submitted for plan review or after it is approved (when the permit is "pulled" for construction).
This permit application fee is usually around $3,000, depending on the estimated construction cost (recorded when the permit application is completed). This construction cost can be underestimated to reduce the permit fee.
If the permit fee is collected after the permit application is approved, the contractor usually pays it when they "pull" the permit for construction.
Pulling the Construction Permit
Only the property owner or a licensed contractor can pull a permit for construction.
If you'd like to oversee the work yourself, you can pull the permit as an “Owner-Builder."
Otherwise, it's best to hire a contractor at this point and have them move forward with construction.
Hire a Contractor
Meet with a few contractors. Have each of them review the project and provide you with a quote for construction.
Don't necessarily go with the lowest quote. This goes for hiring an architect and an engineer as well.
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 premium for more qualified specialists. Better insight and foresight provides for economical design and construction, smoother and faster delivery, and improved project longevity without problems after completion, all of which translates into cost savings for you.
Be sure to do your due diligence, and don't go with the lowest quote unless it's a good fit and you feel confident in their ability.
During the initial stages of construction, be sure 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.
The contractor will be available, but they function more in a business and supervisory role and won't be on site every day.
The superintendent is a good person to know for coordination in case something comes up or you if need to know something. They are onsite and will be more responsive.
Feel free to periodically check on the progress of construction, have the superintendent show you around, and ask them questions. If you see tasks that can improve your building or the project, feel free to make those requests.
During construction, the contractor will coordinate special inspections. A building official from the city and a third party special inspector (or perhaps the engineer of record) will visit the site at key junctures to check the work that is being done.
This may occur, for example, after rebar and formwork is placed (before concrete is poured to make a new foundation), or after wood framing and anchorage is complete (before plywood sheathing is nailed to the shear walls).
For each project phase, the special inspectors will certify that the work follows the building code and approved plans.
Upon completion of construction, the special inspectors will conduct a final inspection, submit the associated documentation, and certify that the project is complete.
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?
Leave us a message below in our website footer.
We're happy to provide you with a complimentary briefing on your building and project.