How Much Does an Earthquake Retrofit Cost?

Seismic Retrofit Cost

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.

• Bolting foundations

• Bracing foundations with a cripple wall then bolting

• Reinforcing shear walls

• Reinforcing or redoing brick chimneys

• Adding an automatic seismic gas shutoff valve

Seismic Retrofit Cost Per Square Foot

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.

Earthquake Valve Installation Cost

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.

Soft Story Retrofit Cost

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.

Earthquake Brace and Bolt Cost

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..

Bolting House to Foundation Cost by Foundation Type

Post and Pier Foundation Retrofit Cost

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.

Mobile Home Earthquake Bracing Cost

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 Earthquake Retrofit Prices

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.

• Foundation installation costs $4,000-$13,000.

• Installing a full basement costs $60,000-$150,000.

Seismic Retrofitting Costs Near You

How Much Does It Cost to Retrofit A House?

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.

Materials for Retrofitting Costs

DIY Retrofitting Costs vs. Hiring A Pro

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.

FAQs

How do I retrofit my house for earthquakes?

Secure your homes walls to the foundation to retrofit your home for earthquakes. You might also consider reinforcing shear walls and chimneys.

Does my home need earthquake retrofit?

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.

How do you tell if your house is bolted to the foundation?

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.