Put a stop to earthquake shimmies and shakes with a solid earthquake retrofit
Earthquake retrofitting involves various stabilizing and strengthening techniques to prevent the home from sliding off the foundation.
Timelines for earthquake retrofitting vary by the size, age, and condition of the home.
An average raised-foundation home takes one week or less to retrofit for an earthquake.
Homes that require simple bolt stabilization can be retrofitted in less than a week.
The average cost of earthquake retrofitting is $6,100, but it can go up to $15,000.
An earthquake-resilient home offers safety and peace of mind in earthquake-prone areas. The size and condition of your home, building techniques, and local building codes all come into play when figuring out how long earthquake retrofitting takes. Simple retrofitting can be done in less than a week, while large homes can take several weeks. Keep reading to see how long it might take to prepare your home against the damaging movements of earthquakes.
Earthquake retrofitting is a process that strengthens a structure against the forces of an earthquake. The primary goal is to keep the home from sliding off the foundation. Depending on your home's design and structure, an earthquake retrofit may involve securing the foundation with bolts or adding plywood to a crawl space. You may also need to reinforce areas supporting your walls.
Older homes, especially those built before 1980, are susceptible to damage due to outdated building codes, materials, and techniques. Hiring a pro to earthquake retrofit your home is often worth it to protect your family from injury and your home from costly damage.
While timelines can vary, the construction work for an earthquake retrofit for an average 2,000-square-foot home takes a few days to a week. That timeline applies to various types of raised-foundation homes built before 1980. A home of similar size located on a hillside will take longer because it requires working with a civil or structural engineer.
| Home Type | Size (Square Feet) | Timeline |
|---|---|---|
| Raised foundation (stem wall, crawl space wall, post and pier) | 2,000 | A few days to 1 week |
| Hillside houses | 2,000 | 2 weeks, possibly longer |
| Raised foundation (stem wall, crawl space wall, post and pier) | 4,000 | 1–2 weeks |
| Hillside houses | 4,000 | 2–4 weeks, possibly longer |
Consult with your contractor to get a more accurate timeline for your home. Ask about their schedule to determine how long it may take before they can get started and if they’re working on several projects simultaneously.
Also, keep in mind that the actual construction work might be the fastest part of the process. Hiring a contractor or engineer, getting permits, and securing financing or grants to fund the work can extend the total project time to four to 12 weeks.
Timelines for earthquake retrofitting can vary from home to home. Not only does the home’s architecture, size, and materials affect how long the process takes, but so does the condition of your home. An older home that isn’t in the best shape will take longer than an updated, new, and well-maintained home.
Home size plays a huge part in the retrofit timeline. Reinforcing the anchors between the house and the foundation takes longer because there are more anchor points. A large home that requires
Contact a local foundation repair company to get an idea of the retrofit depth you need based on your home's size and condition. For example, an older home in disrepair may require a more in-depth retrofit that includes opening walls to reinforce the frame and closing the walls. The larger the home and deeper the work, the longer it takes to complete the retrofit.
Some homes are fairly simple to strengthen and secure, and others require consulting an engineer and several retrofitting techniques to withstand the shaking of an earthquake.
Raised-Foundation Homes: The frame of a raised-foundation home can easily slide off of the foundation during an earthquake. These homes, including stem-wall houses, have crawl spaces underneath them. They need a bolt and brace retrofit, which involves bolting the foundation to the frame and bracing the crawl space with plywood.
Post and Pier Houses: These raised-foundation homes require a continuous concrete footing around the foundation and bracing the crawl space with plywood.
Over-Garage Living Spaces: Homes with living spaces over the garage are known as “soft-story” homes. Because of the large open garage space, the soft story isn’t as fortified as other areas of the home. A retrofit involves strengthening the garage walls and garage door frames to add stability.
Hillside Homes: Homes built on hillsides and steep slopes are particularly susceptible to earthquake damage because the foundation steps down the slope and may include columns or posts supporting areas of the home. These homes require strengthening the foundation, bolting, and wall bracing. However, you’ll likely need to consult a civil or structural engineer in your area to get an earthquake retrofitting plan before construction starts.
California and other states where earthquakes are common tend to have more thorough and complex building codes as added precautions against earthquake damage. Any retrofitting must be done according to these guidelines, which can extend the work time. From getting the permits to waiting on materials and using the latest techniques, meeting code is necessary but can sometimes be time-consuming.
Costs vary as much as timelines. The average earthquake retrofit costs between $3,500 and $8,700. However, homes on hillsides, large homes, and those with rooms over garages can cost up to $12,000 or more. Make sure to get a few estimates to compare the cost and services.
According to the Earthquake Country Alliance—a public and private alliance in California that works to improve earthquake and tsunami readiness—reports that unreinforced masonry, such as stone, bricks, and hollow clay tiles, is more susceptible to earthquake damage. The mortar between bricks isn’t as stable as other building materials and methods.
