Some Bay Area homeowners who may be worried about the fitness of their older abodes during an earthquake are being offered money for retrofits that state regulators say could prevent collapse during a large temblor.
Property owners in designated high-risk areas in the East Bay and on the Peninsula have until Feb. 27 to apply for up to $3,000 to prevent their houses from shaking off their foundations during an quake like the one that rattled Napa three years ago.
The newly expanded Earthquake Brace + Bolt Program has $6 million in grant money available in 2017, enough to retrofit 2,000 homes, said Janiele Maffei, chief mitigation officer for the California Earthquake Authority, which is co-managing the program with the California Office of Emergency Services.
An estimated 1.2 million older wood-frame homes in high-hazard areas of California are missing anchor bolts connecting the houses to the foundations, or have stud walls, known as cripple walls, that are too weak to handle serious shaking.
The crawl spaces of these homes, especially those built before 1940, are vulnerable to collapse in a strong earthquake.
Maffei said cripple-wall damage was common during the 6.0-magnitude South Napa earthquake in 2014 that killed one person, injured more than 200 and caused $360 million in damage. About 1,500 homes were harmed, many of them sliding off their foundations, and it took more than a year before some families were able to return home.
“It’s a particular vulnerability that is very common,” Maffei said. “The kind of damage we’re talking about is what we saw in the Napa earthquake — very destructive. So the cost benefit is absolutely in your favor to do the retrofit beforehand instead of waiting to make repairs afterward.”
Maffei said the earthquake authority prioritized areas based on earthquake risk and the number of older homes. They selected 141 zip codes in 33 cities that are eligible for the grant, including an area along the Hayward Fault stretching from Hayward to El Cerrito and along the San Andreas Fault from San Francisco to Redwood City.
Only homes built before 1979 are eligible for the money, which can be used to place anchor bolts in the foundation and strengthen the cripple walls with plywood sheeting. Bay Area homeowners might have to fork over some of their own money, as contractors usually charge between $5,000 and $8,000 for the jobs, depending on the location and size of the house, Maffei said.
“It was very clear that this was not only an important retrofit but it was one that was cost-effective,” Maffei said. “There are other vulnerabilities we could work on, but this was the one that was most prevalent.”
The authority, which began offering the grants Wednesday, is expecting more than 2,000 homeowners to register. The grantees will be chosen by random selection, she said, and everyone else will be put on a waiting list.
The $6 million available for the program, which is in its fourth year, is a 25 percent increase over last year.
Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite