How Much Does an Earthquake Retrofit Cost?
$3,329 - $7,602
$3,329 - $7,602
Published January 10, 2022Written by HomeAdvisor.
Retrofitting a house for earthquakes costs $5,296 on average and typically falls between $3,329 and $7,602. Large homes and difficult seismic retrofitting costs closer to $10,000. Labor makes up 70% of the total price, so DIY installs average $1,400.
Earthquake retrofitting of a home involves bracing, bolting and reinforcing foundations, walls, roofs and chimneys to resist the seismic shaking caused during an earthquake. It keeps your home on its foundation and minimizes damage.
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|Typical Range||$3,329 - $7,602|
|Low End - High End||$550 - $10,000|
Cost data is based on actual project costs as reported by 63 HomeAdvisor members.
Seismic retrofitting costs anywhere from $500 to $10,000, depending on what you need done, the type of foundation you have and the size of your home. Most homes in earthquake prone areas built before 1980 need one, but even newer houses should get an inspection.
A retrofit helps stop a home from sliding off its foundation. It also reinforces walls, ceilings and chimneys from damage. You can use the following methods independently or together depending on the condition and architecture of your house.
Bracing foundations with a cripple wall then bolting
Reinforcing shear walls
Reinforcing or redoing brick chimneys
Adding an automatic seismic gas shutoff valve
On average, you’ll spend anywhere from $3 to $7 per square foot for a seismic retrofit. On the lower end, you’ll find simple universal foundation plate installation with higher end pricing involving building a cripple wall and adding plywood to shear walls.
Installing an earthquake valve costs $250 to $750 with an average price of $350. In some places, it’s not only required for any home sales, the city also requires and charges for inspections. For example, in Los Angeles, the city fee of $45 covers the city inspector.
The valves themselves run $100 to $250 for most residential uses and $500 to $1,500+ for commercial grades for businesses and apartments.
Retrofitting a soft story costs anywhere from $10,000 to $80,000. For apartment buildings, property owners can expect to pay $80,000 to $350,000 or more.
A soft story is any multi story building with a large opening where a shear wall for structural support would normally go. The most common example for residential homes – a second story over a garage or carport. You’ll reinforce the area around the garage doors and often the adjoining walls to carry more weight and make them more rigid.
Brace and bolt costs anywhere from $500 to $7,000 or more depending on how it’s done. The methods vary depending on the architecture of your home, but include the following:
Anchoring a mudsill: $1,000-$3,000. This process places anchor bolts through the mud sill, also called a sill plate and into the stem wall or cripple wall.
Cripple shear wall bracing: $1,000-$2,500. This process uses plywood sheathing and 2x4 blocking to reinforce the cripple wall.
Cripple wall bolting: $1,000-$3,000. The same process as anchoring to a mudsill, but with the absence of a mudsill.
Universal Foundation Plate (UFP) retrofitting: $500-$1,500. The plates alone run $20 each..
$500 - $2,500
$2,000 - $10,000+
Footing and stem wall
$3,000 - $7,000
$3,000 - $5,000
Post and Pier
$3,000 - $10,000
Retrofitting pier and post costs anywhere from $3,000 to $10,000. It’s an older style of construction that, uses space piers with posts attached to them. Instead of floor joists spanning the foundation (either to the mudsill or a stem wall or cripple wall), these regularly spaced posts hold up the home.
Retrofitting done correctly ties the posts to the piers and the home with T straps or other anchoring material.
Earthquake resistant bracing system (ERBS) or an engineered tie-down system for a mobile home costs $2,000 to $10,000. The systems use one of three methods:
Primary Support Column (PSC) earthquake anchoring costs $2,800-$9,200.
Earthquake resistant bracing system (ERBS) costs $2,000-$4,000. These use anchors in the ground with tie down straps.
Pour a foundation of slab with footings for $6,000-$25,000. Not a common option but provides excellent protection.
Manufactured homes can use either mobile home or traditional home strategies, depending on the foundation type. To use home methods for bracing, you’ll need a foundation or basement.
Average Cost Range
$3,900 - $6,000
$4,500 - $8,000
$3,000 - $5,500
$2,800 - $6,000
Labor makes up anywhere from 60% to 90% of the total price of a retrofit. On average, you’ll spend 70% of the total on labor or $3,000 to $10,000. The actual amount varies based on what your home needs. For example, if you only need bolting, without plates or a new cripple wall, most of the price comes from labor. But if you need plates installed, a new knee wall and sheathing, more money goes into the materials.
$2 - $6 per square foot
$6 - $10 per sheet
$20 - $40 each
$30 - $70 each
$40 - $80 each
Seismic Shutoff Valve
$100 - $300 each
If you understand the code requirements for a retrofit, a DIY install might save you 70%. But even if you do decide to do this project yourself, it’s best to familiarize yourself with the codes and engineering requirements. Find a local structural engineer to inspect your property and recommend reinforcements.
Hire a professional for quick work that meets or exceeds code requirements and gives you the peace of mind from earthquake damage. Repairing a home that has slid off its foundation runs into the tens of thousands of dollars. For a fraction of the price, find a local foundation repair contractor.
Secure your homes walls to the foundation to retrofit your home for earthquakes. You might also consider reinforcing shear walls and chimneys.
Only a professional can tell you if your home needs a retrofit. However, most homes built before 1980 and reside in an earthquake zone tend to need a retrofit.
If your comfortable looking under your house, you can see the bolts sticking through the sill plate or you may see universal foundation plates connecting the wood to the foundation. If you can’t tell, find a local home inspector to look for you.