Range of Costs for Single Family 1 Story Seismic Retrofit San Francisco
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Benefits of Seismic Upgrades: Is Earthquake Retrofitting Worth It in CA?
February 25, 2020
Earthquakes occur suddenly and without warning. The movement on the globe'southward crust can cause astringent harm to older homes. Homes built before 1980 are especially at gamble because many were non built to resist shaking and moving.
Why Retrofit Your Habitation?
The purpose of retrofitting for earthquakes is to keep your home from existence displaced from its foundation—making the building safer and less prone to major structural damage during an convulsion.
The 2014 South Napa earthquake occurred on Baronial 24 at 03:twenty:44 Pacific Daylight Time. This 6.0 M astringent event was the largest convulse in the San Francisco Bay Surface area since the 1989 Loma Prieta convulsion.
Houses shook violently, merely two houses that sit side-by-side in Napa had different outcomes. One stood undamaged, its neighbor had shifted off its foundation with dramatic structural impairment.
Consider this case study on the cost effectiveness of retrofitting.
What Are the Chances of a Major California Earthquake?
California has more than a 99% chance of having one or more magnitude 6.7 or larger earthquakes within the adjacent 30 years, according to scientists.
- For Northern California, the most likely source of such earthquakes is the Hayward-Rodgers Creek Fault (31% in the next 30 years). Such quakes tin can be mortiferous, as shown by the 1989 magnitude 6.9 Loma Prieta earthquake. The Loma Prieta quake caused 63 deaths, 3,757 injuries, and almost $6 billion in damage.
- For Southern California, inside the next 30 years the probability is 60% for an earthquake measuring magnitude 6.7. The southern San Andreas fault is much closer to Los Angeles, running at its closest just 25 miles northeast of downtown through the San Gabriel Mountains, and is capable of unleashing a magnitude 8.two quake throughout all of Southern California. The 2019 Ridgecrest convulsion happened on a brand new mistake line forth the Eastern California Shear Zone.
The new study determined the probabilities that unlike parts of California—including college-risk areas like the Bay Area and the city of Los Angeles—will feel convulsion ruptures of various magnitudes. The new statewide probabilities are the result of a model that comprehensively combines information from seismology, convulsion geology, and geodesy (measuring precise locations on the world'south surface).
What are the Benefits of Retrofitting?
Convulsion retrofitting (seismically retrofitting) a house is washed to forestall displacement from the structure'southward concrete foundation. This makes a building safer and less likely to endure damage during an earthquake.
Retrofitting single-family homes is considered ane of the cheapest seismic improvements bachelor. A foundation bolting procedure commonly costs a few 1000 dollars and tin exist washed inside several days without the residents moving out.
What is the Cost of Retrofitting?
While there isn't a standard price for earthquake retrofitting a domicile, the range is usually about $3,000 to $7,000. Larger homes, those built on hillsides, and those with basements or rooms over garages will typically cost more than to retrofit. Many houses that crave only bolting cost well-nigh $3,000.
Why Retrofitting is Necessary?
Reason 1: Increase safety
Properly retrofitted houses are made stronger confronting earthquake shaking and impairment. This means your business firm is safer, and y'all've reduced the take chances of injury or even death in a devastating earthquake.
Reason ii: Financially protect your investment
You have invested a lot of time and money into your older house. Without a seismic retrofit, the repair costs you'd face after a damaging convulsion could be very costly. Call back of it this fashion: it's a lot cheaper to retrofit your business firm now than it is to repair information technology after an earthquake.
Reason three: Brand sure you lot have a place to live
If you have non seismically retrofitted your house and an convulsion amercement it, it could take years to repair, and you may accept to have out a loan to brand repairs. Likewise, keep in mind that people oft have to move out of their home during repairs, and rental costs typically go upwards in affected areas post-obit a major disaster. That means you could be paying repair costs, rental costs, and your mortgage—all at the same time!
How to Retrofit
All Californians should have their homes assessed to determine if they need to be retrofitted. Every bit mentioned earlier, the 2019 Ridgecrest earthquake happened on an unknown mistake and the 2014 Napa earthquake happened on an unexpected fault. The retrofit work of seismic upgrades volition likely:
- Meliorate a home's ability to proceed residents safety during an earthquake and the house habitable after a major disaster.
- Reduce repair costs after a seismic event.
- Reduce earthquake insurance premiums.
The goal of retrofitting is for homeowners to shelter in place and survive a major earthquake. Earthquake reinforcement volition reduce harm to the construction and go along the domicile habitable.
Retrofitting will continue your house from beingness displaced from its foundation. The terms house bolting and foundation bolting are oftentimes used interchangeably with earthquake retrofitting.
Cripple Wall Bracing
Cripple walls are short walls that residue on a business firm's foundation and back up the floor and outside walls. When these walls are not braced, they may shift during an earthquake. When this occurs, the chances of astringent damage to your business firm and injury to individuals increases. Bracing cripple walls strengthens structures by increasing stability, and the procedure typically helps minimize damage to houses. Meet the paradigm to a higher place to empathise how new elements in the crawl space heighten the house's convulsion resistance.
Foundation Bolting
Houses that aren't bolted to their foundation can move during an earthquake. Houses that move off their foundation will cause significant damage and may be costly to repair. The bolting process requires that holes are drilled through the sill plate on a foundation and ballast bolts are installed. Sometimes, at that place isn't enough infinite to drill, and steel plates will also need to be attached. These bolts must be properly installed to be effective.
Reinforce or Strap Chimneys
Brick chimneys account for the virtually common harm during larger California quakes. When chimneys collapse, bricks can become deadly projectiles. At least 15,000 brick chimneys were damaged in Los Angeles during the 1994 Northridge convulsion. In Napa, near half of the residential buildings damaged were due to brick chimneys.
Our Chief Mitigation Officer, Janiele Maffei, says homeowners should ask themselves:
"If this does autumn, could this fall on my neighbour's house? Could this autumn where I always park my car? Could this fall where my children play?"
To keep bricks from falling through the roof during an earthquake, hither are some reinforcement options:
- One option is to add layers of plywood on the roof around the chimney.
- Another is to remove the upper part of the chimney, which tin can twist and plough during shaking, and replace it with metal.
- A third option is to add together a diagonal steel brace to the chimney.
Even with those improvements, the chimney all the same could collapse. In Los Angeles County a more extensive retrofit is required. It involves removing the chimney completely or rebuilding information technology.
If the homeowner doesn't need the chimney to be functional, the retrofitting could be every bit uncomplicated every bit placing a steel tube down the structure and filling information technology with concrete.
Reinforce Masonry Walls
If your older dwelling has poor wall anchorage, consult a certified engineer on the almost cost-effective mode to strengthen it. A qualified contractor can add new anchorage and continuous ties across the roof. Walls can also be strengthened between the connections between the roof and floor joists.
Soft Story above the Garage
Many soft story homes have a story with a bedroom or playroom above fastened garages. Such a room opening has little or no stiffness or shear strength. Such a story is "soft" in its resistance to lateral move such as an earthquake.
Soft story atmospheric condition tin can sometimes be improved by installing new plywood sheathing or steel reinforcements on each side of the garage door. Some garage doors crave a steel frame to be properly retrofitted for earthquakes, which tin can exist done through an engineered retrofit.
Hillside House
Houses on steep hillsides are often prepare on tall, narrow posts or columns, with or without diagonal bracing, and may take walls that "step down" the hill and may not be properly braced to withstand earthquakes. Without seismic retrofitting these homes can suffer significant damage or even collapse during an earthquake.
Learn more than about hillside houses.
Post and Pier Firm
A mail service-and-pier business firm is built on wooden posts or physical piers set into the ground to bear the weight of the house, and is vulnerable during an earthquake to shifting, and potentially collapsing.
To withstand the effects of earthquakes, post-and-pier houses should receive a new continuous-perimeter foundation, with any cripple walls bolted and braced. Acquire more virtually the retrofitting of a post and pier house.
Install Gas Shut-off Devices
Know how to turn off the gas or learn if you should take an automatic gas shut-off valve installed that is triggered by strong vibrations. Consult with your local gas company before doing any work.
From Red Tag to Light-green
Local, state and federal government utilise a color-tagged system--classified by a red-yellowish-dark-green color— to correspond the severity of convulsion damage or the overall condition of a home or edifice. The red and xanthous tags are an indicator of whether the dwelling is habitable. Red tagged homes are accounted likewise dangerous to live in. With proper seismic retrofitting, the homes may receive a green tag.
Is Your Firm at Risk for Earthquake Damage?
Prepare your domicile Earlier an earthquake. Decrease your risk of harm and injury from an earthquake by identifying possible structural risks and geologic hazards near you. Visit CEA's faults by county map to get the facts about convulsion hazards nigh your home.
Consider earthquake insurance to protect the fiscal investment you have in your habitation. CEA policies provide you with the force to rebuild and repair, funds to live elsewhere while repairs are being made to your home, and help replace your personal belongings if information technology is damaged in an earthquake.
Contact your insurance agent or residential insurance company to find the CEA policy that is correct for yous.
How to Protect Your Dwelling house before an Earthquake Strikes
An earthquake's powerful shaking tin rupture the world, trigger landslides, and turn the surface of the earth to liquid. Your home too may be vulnerable to serious structural damage if it was congenital before 1980.
Become tips on how to prepare and protect your home against earthquake damage.
Agreement Structural Risks
Earthquake safety preparation requires your understanding of the potential structural threats to your home in case of an earthquake.
A seismic retrofit involves strengthening your domicile's foundation to go far more than resistant to shaking. CEA offers earthquake home insurance premium discounts for houses and mobilehomes that take been properly retrofitted.
Notice out nearly seismic retrofit grants to assistance pay for retrofits nether the Convulsion Caryatid & Bolt Programme, and the CEA Brace & Bolt program.
Evaluating Geologic Hazards
With nearly sixteen,000 known state faults, most of us live within thirty miles of an agile fault. All of California is earthquake country. It is not just Los Angeles, San Diego, and the San Francisco Bay Area that are dwelling to active faults. Every region of the state holds a caste of earthquake risk.
Detect out well-nigh faults in your surface area by visiting the CEA take a chance map for each canton. This information will help you create an earthquake precaution checklist.
Then learn about your abode's structural risks and the steps y'all tin have to seismically strengthen your house. California Role of Emergency Services MyHazards can assistance you lot find out if the area where y'all live or work is prone to earthquake-induced landslides.
Do I Need Earthquake Insurance?
Consider these facts in the result of a large earthquake:
- Earthquakes tin can cause all-encompassing damage to the foundation, siding and roof of homes. Older homes congenital before 1980 on a raised foundation are especially vulnerable if they are not retrofitted.
- Without residential earthquake insurance you volition be responsible for all repair and/or rebuilding costs.
- Government disaster assistance, if available, but comes in the course of a pocket-sized grant or capped loan, which may encompass simply a portion of your repair costs.
- Without Loss of Use convulsion coverage—which includes covering additional expenses of living elsewhere—you'd notwithstanding exist paying your mortgage plus temporary housing hire during the fourth dimension repairs are underway.
CEA affordable earthquake insurance policies let y'all select the coverage that fits your budget. Our insurance rates, based on the latest science and research, are determined by several factors including your home's age, location well-nigh a error, foundation type, structure type, and roof blazon.
Brace & Bolt Programs
If your dwelling was congenital earlier 1980 it is more vulnerable to convulsion harm and collapse. Convulsion reinforcement or seismic retrofitting volition strengthen your abode confronting earthquake damage. Homeowners with properly retrofitted eligible houses can receive a CEA insurance premium discount of up to 25%.
Nosotros offer two programs to help eligible homeowners pay for their retrofits. Owners of hillside houses may exist eligible for these programs if their house qualifies under California Existing Building Code Chapter A3.
- CEA Brace + Bolt (CEA BB) offers grants of up to $iii,000 to electric current CEA policyholders for houses that qualify.
- Earthquake Caryatid + Bolt (EBB) offers grants of up to $iii,000 to homeowners in certain college-earthquake risk Cipher Codes for houses that qualify.
Get Convulsion Insurance Discounts
Observe out about brace and bolt seismic retrofit grants to aid pay for retrofits under the Convulsion Caryatid & Commodities Program, and the CEA Brace & Bolt programme.
Whether or not yous participate in a grant program, if you properly retrofit your eligible house (eligibility includes having been built before 1980 and of wood frame construction), you could receive a CEA insurance premium discount of up to 25%.
Become a Free Estimate (Figurer)
Consider earthquake insurance to protect the financial investment you have in your home. CEA policies provide you lot with the force to rebuild and repair, funds to live elsewhere while repairs are existence made to your home, and help replace your personal belongings if it is damaged in an earthquake.
Contact your insurance amanuensis or residential insurance visitor to notice the CEA policy that is correct for you.
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Source: https://www.earthquakeauthority.com/Blog/2020/Benefits-Seismic-Upgrades-Why-Retrofit-Your-Home
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