How Much Does It Cost to Retrofit a Home for Earthquake Protection?
If your home is located in an area known to be hit by earthquakes, you may want to consider having it seismically retrofitted to protect it from serious damage in the event of an earthquake. Homes built before the 1970s were not constructed with the right type of technology or techniques to protect them from earthquakes. Even some newer homes may have been built without the latest protection techniques. This means that older homes should undergo retrofitting to brace and strengthen them to withstand an earthquake.
Retrofitting can be costly but is a worthwhile investment if you live in an area that sees high seismic activity. The average range for seismic retrofits runs between $3,000 and $7,000. Most homeowners pay around $4,900 for foundation bolting and mudsill anchoring in a 2,000 sq.ft. home. The cost for retrofitting your home can run as low as $800 for bracing a crippling wall in a 1,200 sq.ft. home to as high as $20,000 to retrofit a 3,000 sq.ft. home with a soft story and a shear wall reinforcement.
Cost to Earthquake Retrofit a House
| Earthquake Retrofitting Cost | |
|---|---|
| National average cost | $4,900 |
| Average range | $3,000-$7,000 |
| Minimum cost | $800 |
| Maximum cost | $20,000 |
In this guide
Seismic Retrofit Cost per Sq.Ft.
Earthquake Retrofitting Cost by Type of Home
Foundation Retrofit Cost by Foundation Type
Earthquake Retrofitting Cost by Technique
Labor Cost of Earthquake Retrofitting
Cost to Retrofit a House Without Cripple Walls
Enhancement and Improvement Costs
Additional Considerations
FAQs
Earthquake Retrofitting Cost by Project Range
Do I Need to Retrofit my Home?
A homeowner may want to retrofit their home for earthquakes for many reasons. If you live in an area with regular earthquake activity, you may consider adding earthquake coverage to your homeowner’s policy. If your home was built before 1980, you might be required to have your home retrofitted to obtain the insurance.
Retrofitting your home helps prevent your home from foundation replacement, which can result in significant structural damage and high repair costs. Any home built before 1980 should be retrofitted if you live in an area with earthquake activity because your home is likely not secured to the foundation, making it less safe in the event of an earthquake. Retrofitting also provides you with better financial protection for one of your most valuable assets, your home.
Seismic Retrofit Cost per Sq.Ft.
The cost to earthquake retrofit a house will be affected by the square footage of your home. On average, you can expect to pay between $1.75 to $3.00 per sq.ft. Larger homes are more costly to retrofit, based on more significant square footage and the likelihood of having architectural components that require additional processes for retrofitting. Below you will see some of the common square footage home sizes, along with the estimated seismic retrofit cost.
| Square Footage | Average Cost to Retrofit (Labor Included) |
|---|---|
| 1,200 sq.ft. | $2,250 - $4,400 |
| 1,500 sq.ft. | $3,150 - $5,000 |
| 2,000 sq.ft | $3,400 - $6,800 |
| 2,500 sq.ft. | $4,000 - $7,400 |
| 3,000 sq.ft. | $5,200 - $8,500 |
Earthquake Retrofitting Cost by Type of Home
Certain types of homes or aspects of your home increase the earthquake retrofit cost. These retrofits require more labor, alternative methods for supports, or a combination of methods to protect the structure properly. With these special considerations, the home’s structure makes it more prone to damage from earthquakes which can make having it retrofitted even more important. Below you will see some types of homes requiring special retrofitting and the average cost to retrofit each.
| Type of Home | Average Cost to Retrofit (Labor Included) |
|---|---|
| Mobile Home | $2,000 - $8,000 |
| Regular Home | $3,000 - $7,000 |
| Hillside House | $5,000 - $8,000 |
| Soft Story | $10,000 - $20,000 |
Mobile Home Earthquake Retrofit
You can expect to pay between $2,000 and $8,000 to retrofit a 1,000 sq.ft. mobile home for an earthquake. Mobile homes are retrofitted by installing an earthquake resistant bracing system that ties the mobile home down to provide greater support. The most common ways to create this bracing system include anchoring the home with support columns or placing anchors in the ground and affixing them to the home with tie-down strips. In rare cases, the homeowner may choose to add an entire foundation. However, the cost of this is significant. It is very uncommon unless the homeowner had other reasons for laying a foundation.
Regular Home Retrofit Cost
The average cost to retrofit a regular home of around 2,000 to 2,500 sq.ft. is between $3,000 and $7,000. The cost to retrofit a regular home will be based on the home’s size and the foundation type. Retrofits for a regular house include anchoring to mudsills 1, providing support for cripple walls, reinforcing walls, and bolting the home into the foundation.
Hillside House Retrofit Cost
Earthquake retrofitting for a house built on a hillside costs between $5,000 and $8,000. Hillside homes tend to have lateral weakness in their support structures, making the home unsafe in the event of an earthquake. The weakness is most often caused by the plywood 2 supporting the home on a stepped foundation. Weakness in the supports leads to significant home damage, sometimes resulting in a total loss. Retrofitting a hillside home involves adding foundation plates and anchors to provide the needed support.
Soft Story Retrofit Cost
One of the most expensive homes to retrofit is a soft story home, costing between $10,000 and $20,000. While a soft story is most often found in apartment buildings, there are homes with this design. In a soft story home, you typically have a large opening in a space that would normally have a wall or structural support. A good example of this with residential dwellings is additional stories over garages. Retrofitting involves reinforcing the area around the garage door or open port so that the walls adjoining it can support more weight.
Foundation Retrofit Cost by Foundation Type
The type of foundation that your home sits on affects the cost of retrofitting a house. Your foundation affects the retrofit cost because different types of supporting structures need to be used based on your foundation. Also, some foundations require more support than others, and certain foundations require more labor for the retrofitting process. Below you can see the most common home foundation types and the average cost for retrofitting each based on a 2,000 to 2,500 sq.ft. home.
| Type of Foundation | Average Retrofit Cost (Labor Included) |
|---|---|
| Slab | $1,000 - $3,000 |
| Brick | $1,800 - $8,000 |
| Basement | $3,000 - $5,000 |
| Post and Pier | $3,000 - $10,000 |
| Footing Stem Wall | $3,500 - $7,200 |
| Thin/Old Concrete | $5,000 - $9,000 |
| Permanent Wood | $5,000 - $10,000 |
Earthquake Retrofit Slab Foundation
Retrofitting a home with a slab foundation 3 costs between $1,000 and $3,000. Houses built on slabs do not have crawl spaces, nor do they have cripple walls that can be reinforced. If your home is newer and was built to code, then it is likely that your house was properly bolted and anchored to the slab. If not, then a professional retrofitter will drill holes in the slab for anchor bolts and affix straps to complete the retrofit.
Earthquake Retrofit Brick Foundation
If your home has a brick foundation, retrofitting costs from $1,800 to $8,000, depending on the condition of the bricks and mortar that make up the foundation. With a brick foundation, the base of the house is a mudsill that sits on top of the brick. It is this base that is mortared to the brick. Wear, elements, and time lead to a weakening of the mortar, so your professional needs to check the condition before proceeding. The most common retrofitting needs with a brick foundation are anchoring the structure to the mudsill and supporting the crippling wall.
Basement Foundation Retrofit
A retrofit on a home with a basement foundation runs between $3,000 and $5,000. Basements are not always common in areas with significant seismic activity, except with older homes. This means many homes with basements need to be retrofitted to provide them with greater stability in the event of an earthquake. Retrofitting a home with a basement requires plywood, bolts, and metal wood connectors framed together to ensure that the house is properly connected to the basement and that the basement can stand up to the energy from an earthquake. Top plate ties and mudsill bolting are often part of basement retrofit processes.
Post and Pier Foundation Retrofit Cost
The cost to retrofit a post and pier foundation falls in the range of $3,000 to $10,000. This type of foundation is most often found in older homes and consists of spaced piers with posts affixed to them. You will not find joists in this type of foundation but instead either a mudsill or cripple wall. To retrofit this type of foundation, you need to have the posts affixed to the pairs using anchoring material such as T-straps.
Footing and Stem Wall Foundation Retrofitting
Footing and stem wall foundation retrofitting costs $3,500 to $7,200. These houses consist of a wood-framed base floor that sits directly on a perimeter foundation made of concrete. When your stem-wall home needs to be retrofitted, foundation plates need to be installed beneath the floor, and the floor will need to be bolted to the plates to create greater durability.
Thin/Old Concrete Foundation Retrofit
A costly type of retrofit is retrofitting a home with a thin concrete foundation. This type of retrofit runs between $5,000 and $9,000 to complete. If portions of the concrete are old or too weak, you may be advised to remove or reinforce it before retrofitting. Retrofitting will be similar to the process of retrofitting a slab, but plates will likely be added to compensate for the thin concrete before bolting.
Permanent Wood Foundation Retrofit
Homes with permanent wood foundations are not designed to withstand the force of an earthquake. You can expect to pay as high as $5,000 to $10,000 for retrofitting. In some cases, this retrofit involves the replacement of portions of the foundation. If replacing the foundation is not possible or too costly an endeavor, retrofitting will involve installing piers and bearing plates into the ground before affixing them to the home.
Earthquake Retrofitting Cost by Technique
The strategy that your retrofitter employs will drastically affect the overall cost of the project. While some processes can be used alone, others will be used in tandem to create a more secure support for your home. For example, an earthquake brace and bolt includes multiple processes. Below you will see the most common retrofit techniques and the average cost for that portion of the project for homes between 2,000 and 2,500 sq.ft.
| Retrofit Technique | Cost (Labor Included) |
|---|---|
| Cripple Wall Bracing | $800 - $2,000 |
| Cripple Wall Bolting | $900 - $2,400 |
| Anchoring to Mudsill | $1,000 - $2,500 |
| Foundation Bolting | $1,000 - $3,000 |
| Shear Wall Reinforcement | $2,500 - $6,000 |
Cripple Wall Bracing Cost
Cripple wall 4 bracing runs between $800 and $2,000, depending on the size and complexity of the wall. Cripple walls are shirt stud walls used to enclose a crawl space between the home. They need to be reinforced and braced, usually with plywood. On their own, most older cripple walls cannot handle the movement that occurs during an earthquake, and that may lead to collapse or the home falling from the foundation. Bracing the cripple walls minimizes movement and ensures that the home is more secure.
Anchoring Cripple Wall to the Floor
It can cost you between $900 and $2,400 to anchor your cripple wall. The anchoring process includes bolting the wall to the floor above. Bolting it to the foundation will not be enough to provide the needed support. The process is done through shear bolting. It may also involve creating a frame on the interior of the cripple wall and bolting this to both the wall and the floor above.
Anchoring to Mudsill
Anchoring your foundation to your mudsill 1 runs between $1,000 and $2,500 and is a popular option with brick foundation homes or homes with crawl spaces. The cripple wall of your home’s crawl space is anchored onto the mudsill of your foundation. This is part of the foundation bolting 5 process, as the cripple wall and mudsill can slide right off the foundation. The mudsill, cripple wall, and foundation need to be bolted together for the best stability.
Your mudsill may need to be anchored to a foundation plate, which will allow it to support an increased load. URFP are improved foundation plates designed for this purpose that are popular options due to their vertical clearance and adjustability.
Bolting House to Foundation Cost
You can expect to pay between $1,000 and $3,000 to have your house bolted to your foundation. This is the bare minimum earthquake retrofitting: anchoring your home directly onto the foundation. It is a popular option with slab foundations. This is what helps keep your home from sliding off the foundation and being damaged during an earthquake. This is sometimes known as anchor bolting and means that large bolts are sunk through the base of your home and into the foundation.
Shear Wall Reinforcing
It costs between $2,500 and $6,000 to reinforce shear walls during the retrofitting process. Sometimes in top-heavy structures, such as an apartment above a garage, the shear walls themselves need extra reinforcement. This can be done on both the vertical and horizontal surfaces of the upper story. Steel grates are commonly used, but this process can sometimes be done with additional stud reinforcement on the interior of the walls.
Labor Cost of Earthquake Retrofitting
The most costly part of earthquake retrofitting is labor, which comprises about 70% of the cost, though it can be as low as 60% to as high as 90% of the total project. Total labor costs for most retrofits run between $3,000 and $10,000, which includes the initial assessment and plan development for the retrofit.
The percentage that you pay in labor depends on the strategy that your professionals choose to employ. Bolting is often mostly labor, where installing new sheathing or walls costs more in materials. The labor costs for the projects are warranted as most projects take up to a week to complete. In more complicated cases with older homes, it may be beneficial to get an assessment from a seismic retrofit engineer who charges between $100 and $300 for an assessment. In most cases, an assessment by the retrofit company will suffice.
Cost to Retrofit a House Without Cripple Walls
Some homes do not have cripple walls, which can mean a lower cost for the overall project, as bracing and bolting this section are unnecessary. However, the joists of the home need to be bolted to the mudsill and to the foundation to prevent the home from sliding off. This includes the floor joists, rim joists, and end joists. All of them need to be bolted to the mudsill and foundation to secure the home. Homes without a cripple wall are at more risk for damage than those with them.
Enhancement and Improvement Costs
Reinforce or Strap Brick Chimney
Reinforcing or strapping a brick chimney costs between $2,000 and $8,000, depending on the location and size of the chimney. If a chimney is not properly reinforced, is damaged, or in other ways unsecured, it can lead to more damage to your home in the event of an earthquake. If your chimney falls away from the home, it can lead to costly foundation issues. In many cases, straps will be applied to secure the chimney. However, if it is pulling far away, the installation of piers may be required.
Reinforce Masonry Walls
Reinforcement of masonry walls costs between $3,000 and $10,000, depending on the number of walls being reinforced and their size. Weak walls lessen the structural integrity of your home and make it more susceptible to damage during an earthquake. Walls will typically be reinforced horizontally and vertically by using truss or galvanized steel wire ladder. This material will be laid in the mortar in between the blocks or bricks.
Earthquake Gas Shut Off Valve Installation Cost
You can expect to spend between $200 and $500 if you need to have an earthquake gas shut-off valve installed in your home. Gas lines rupturing are a severe hazard when an earthquake occurs that can lead to significant damage to your home and injury to you and those in your household. These valves are designed to shut off the gas feeding to the lines in your home if seismic activity is detected.
Additional Considerations and Costs
- Insurance. In most cases, earthquake retrofitting is not covered by insurance, but you may qualify for a lower insurance rate once it’s done.
- Seismic review. If you are unsure of the risk to your property, you can opt to have a seismic review done of your area, which tells you how you may be impacted. Keep in mind that it can be impossible to predict damage. A review costs between $100 and $500, depending on the level of detail.
- Licensed professionals. All professionals who work on earthquake retrofitting your home should be licensed and have a permit for the job. Make sure you follow up to confirm both.
- Financing. PACE financing may be available to you to help meet the costs of the retrofit. This is an affordable financing option that is available for upgrades that include energy efficiency and storm protection. This is not a loan, but a property assessment, that allows you to borrow the money based on the property you are updating at a low interest rate. Speak to your contractor for more information.
- Tags. When inspecting homes for earthquake damage, authorities at the federal, state, and local levels inspect your home and rate the condition of the property with a tagging system. The system uses red, yellow, and green tags. Red means uninhabitable, and green tags mean safe to live in. Proper retrofitting gives your home a greater likelihood of being green tagged.
- Additional story. When your home is retrofitted for an earthquake, it is prepared to support its current structure and weight. That means adding a floor to your home may require different or additional support. If you plan to add a story to your home in the future, you should let your retrofit professional know. If your house is already retrofitted and you just added a story, you may need additional support.
- Preparation for earthquakes. To prepare for an earthquake, make sure you secure heavy objects and appliances with brackets or straps, prepare a survival kit with food and medical supplies, and keep it in a safe location in your home where you can take shelter during an earthquake. This may be in a doorway or a reinforced area of the home.
FAQs
- What are cripple walls?
Cripple walls are wooden floors and stud walls that are built on top of a foundation. These provide additional support for the home and crawl space. Since they are responsible for supporting much of the weight of the house, if they are not properly braced, they can collapse during an earthquake.
- Do I need earthquake insurance?
Deciding on earthquake insurance depends on the area you live in and the financial investment in your home. Earthquakes can cause extensive damage that can be costly to fix. In some cases, you may be granted disaster assistance. However, there is usually a cap that is often not enough to cover repairs. If you live in an area with heavy seismic activity, earthquake insurance is likely a good investment.
- How to tell if your house is bolted to the foundation?
The best way to check how your foundation is secured is by looking under your house. Your house is bolted to the foundation if you can see either foundation plates connecting to wood or bolts sticking through the plate. If you are unsure, a home inspector can assist you.
- What magnitude earthquake can a house withstand?
This depends on many factors, including the size, location, age of the home, depth and proximity of the epicenter of the earthquake, and whether the house has been reinforced or retrofitted. Many existing homes in the United States can withstand earthquakes to a magnitude of 7.0 without significant damage.
- How much does it cost to retrofit a mobile home?
Mobile homes require a foundation for earthquake retrofit. If they have a foundation, they are subject to most of the same costs as other homes. Costs run from $2,000 to $8,000.
Remodeling Terms Cheat Sheet
Definitions in laymen's terms, cost considerations, pictures and things you need to know.See full cheat sheet.
2 Plywood: An engineered construction material manufactured from thin slices of wood glued together in alternating grain patterns for strength
3 Slab foundation: A layer of concrete, poured over a prepared surface of soil or gravel, that supports a house or other building structure
How much does it cost to retrofit a home for earthquake protection in my city?
Cost to retrofit a home for earthquake protection varies greatly by region (and even by zip code). To get free estimates from local contractors, please indicate yours.
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