Repair & retrofit
Earthquake retrofit for Los Angeles homes
We bolt older houses to their foundations and brace the short walls in the crawl space, so the house stays where it is when the ground moves. Most retrofits take one to three days on site.
Who needs a retrofit
Many Los Angeles houses built before 1980 sit on raised foundations with a short stud wall, called a cripple wall, between the concrete and the floor. Older houses often have few or no anchor bolts holding the wood to the concrete. In a strong earthquake, an unbraced cripple wall can fold sideways and the house can slide off its foundation. A retrofit closes both of those gaps.
Signs your house may need one
- It was built before 1980 and has a crawl space under the floor.
- From the crawl space, you can't see bolts with square plate washers every few feet along the sill plate.
- The short walls between the foundation and the floor are bare studs, with no plywood.
- You're buying or selling, and the inspector flagged the foundation or the bolting.
What the work includes
- Anchor bolts through the sill plate into the concrete foundation, with plate washers.
- Plywood shear panels nailed to the cripple walls to brace them.
- Connections between the sill, the cripple walls and the floor framing above.
- While we're under the house: water heater strapping and gas shut-off valves, if you want them.
Earthquake Brace + Bolt
If your house qualifies, California's Earthquake Brace + Bolt program pays up to $3,000 toward the retrofit, and households earning $94,480 a year or less can apply for up to $7,000 more. We're an approved contractor in the program.
How the grant works →Permits and plans
In the City of Los Angeles, bolting and bracing is permitted work. Most one- and two-story houses with short cripple walls can be retrofitted under LA City Standard Plan #1, a pre-approved plan, so you don't need to hire an engineer. Houses with taller cripple walls, or on a steep hillside, may need an engineered plan instead. We'll tell you which applies after the inspection, pull the permit, and schedule the city inspection. Keep the finaled permit: buyers and insurers may ask for it.
How a retrofit is built
A section through a raised foundation after a retrofit. Tap a part in the key to highlight it.
Questions
How long does a retrofit take?
Most bolting and cripple-wall bracing jobs take one to three days on site. The written estimate includes the schedule.
Do I need to move out during the work?
No. The work happens in the crawl space and around the outside of the house. Expect some noise during the day.
Do I need a permit?
Yes. In the City of Los Angeles, bolting and bracing is permitted work, usually under LA City Standard Plan #1. We pull the permit and schedule the city inspection.
Can I use the Brace + Bolt grant?
Possibly. EBB pays up to $3,000 toward a retrofit for wood-frame houses built before 1980 on raised foundations, in participating ZIP codes. Registration opens for a limited time each year at crmp.org, and the work must be done by a contractor in the program's directory. We're in it.
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