Brace + Bolt Retrofits are smaller retrofits performed on single-family residential homes. These retrofits often do not even require engineering. They consist of installing anchor bolts to anchor the wooden structure to its concrete foundation and bracing cripple walls to prevent the house from collapsing in the case of an earthquake. Most of these retrofits cost between $3,000 & $7,000, and government programs can often cover up to $3,000 of that amount.
These retrofits do not usually require engineering work to be performed. There is a generic prescribed seismic strengthening plan that applies to most single-family residential homes that can be braced and bolted. As long as a house's cripple wall, the short wood wall enclosing the crawl space, is under 4 ft tall, the generic plan will work well.
The brace and bolt retrofit serves a few main purposes:
- Bolts strengthen the connection between the wooden house and the concrete foundation, preventing sliding.