Residential Seismic Retrofits

Are you a homeowner asking yourself if a seismic retrofit is a good investment?

A residential earthquake retrofit typically involves modifying a house or building to make it more resistant to earthquake damage. Earthquakes often knock homes off their foundations. But have you considered the resulting damage to interior systems like electrical wiring and plumbing?

(Photos would be good here – examples of what can happen.)

In residential retrofits the following techniques are common:

Foundation bolting: This work adds or reinforces anchor bolts that connect the house’s wooden framing to its masonry or concrete foundation. The bolts help to secure the structure to the foundation, preventing it from shifting or sliding during an earthquake.

Strengthen floor-to-wall connections: This requires reinforcing connections between the floor structure and the exterior walls of the house. It may involve adding metal connectors or plywood panels to enhance the stability and integrity of the structure during an earthquake.

Cripple wall bracing: Cripple walls are short wood-framed walls. They sit on top of the foundation, supporting the main floor of the house. During an earthquake, these walls are vulnerable to collapse. To create the bracing, we add reinforcement such as structural panels or plywood sheathing to strengthen the cripple walls and improve their resilience to earthquake forces.

There is good news for homeowners. The State of California offers a program once a year called Earthquake Brace and Bolt (EBB). The program offers grants toward an earthquake retrofit during a specific application window. Eligibility for the $3,000 grant requires that you own and live in the home you want to retrofit, you live in an eligible zip code, your house has a raised foundation, or crawl space under it, that it is built on level ground or a slight slope and finally, you haven’t completed a “brace and bolt” earthquake retrofit.​