Strengthen Your House
Would you like to receive up to $3,000 toward an earthquake retrofit of your house? The Napa Earthquake Brace + Bolt program provides homeowners up to $3,000 to strengthen their foundation and lessen the potential for earthquake damage.
Many homeowners will decide to hire a contractor to do the retrofit work instead of doing it themselves. A typical retrofit may cost between $3,000 and $7,000 depending on the location and size of the house, contractor fees, and the amount of materials and work involved. If the homeowner is an experienced do-it-yourselfer, a retrofit can cost less than $3,000.
The Napa EBB program relies on adherence to the California Building Code, Appendix Chapter A3. Chapter A3 is a statewide building code that sets prescriptive standards for seismic retrofits of existing residential buildings.
Chapter A3 allows:
- the building department to approve the retrofit for a house with a 4-foot or shorter cripple wall, without requiring plans prepared by a registered design professional (architect or engineer).
- retrofits for houses with cripple walls higher than 4-feet with plans prepared by a registered design professional.
Surrounding the crawl space under the first floor, many houses have a short wood framed wall ("cripple wall") that needs to be strengthened to prevent the house from sliding or toppling off of its foundation during an earthquake. Strengthening involves adding anchor bolts and plywood bracing in the crawl space.
Napa EBB is limited to funding residential retrofit expenses in the crawl space that:
- Bolt: add anchor bolts and sill plates in the crawl space to improve the connection between the wood framing of the house and its concrete foundation to help keep the house from sliding.
- Brace: strengthen the cripple walls in the crawl space with plywood will help keep the house from toppling off of the foundation during an earthquake. Strengthening cripple walls enables them to function as shear members, significantly protecting the house from collapsing.
- Strap the Water Heater: properly strap the water heater to reduce the likelihood of water and fire damage, and to protect the water supply.
Houses that meet Chapter A3 specifications are typically:
- constructed before 1979
- built on a level or low slope
- constructed with a 4-foot (or less) cripple wall under the first floor
- constructed with a cripple wall between 4 feet and 7 feet (requires an engineered solution)
- have a raised foundation
2015 Napa EBB PROGRAM ZIP CODES
Homeowner registration is currently closed. Napa EBB retrofits are currently in progress in these areas:
ZIP Codes in Northern California