Editorial|14 January 2016
The Earthquake Brace+Bolt program is offering up to $3000 in over 100 zip codes towards a retrofit of older wood-frame homes with a ‘cripple wall’ or ‘stem wall’ (these are types of crawl spaces) below the first floor. Registration is open only from January 20 to February 20, 2016, so jump on it. Once registration ends, qualifying homeowners will be selected through a random drawing; you will be notified if chosen or are placed on a wait list.
We met with Sheri Aguirre (Managing Director of Earthquake Brace and Bolt) and Janiele Maffei (Chief Mitigation Officer of the California Earthquake Authority) in Sacramento to learn more about the program two months ago. We also talked with Margaret Vinci at Caltech, who had a very positive experience retrofitting her Pasadena home through this program; her out-of-pocket cost was only $1,000. We also met with her retrofit contractor to gain their perspective. Our only wish is that Earthquake Brace+Bolt could provide funds for many more homes. By their estimate, there are about one million California homes in need of retrofit, and so at this rate, it would take 1,000 years to get the job done. But it is nevertheless a great incentive to do something that will lower your likely cost of earthquake damage, and increase your seismic safety—at a deep discount.
Earthquake Brace + Bolt retrofit is guided by ‘Appendix Chapter A3’ for light, wood-frame houses. Qualifying foundations are concrete and reinforced masonry and include cripple walls or stem walls. In a ‘cripple wall,’ (a terrible term) there is a short wall between the foundation and first floor, so generally as you enter the home you will walk up several stairs. In the retrofit, plywood is added between the foundation and first floor to resist shear forces, and the wall is bolted to the foundation. In a ‘stem wall,’ there is a crawl space, but the first floor lies directly on the foundation. This generally involves only a bolt-down.
To decide if this makes sense for you, use the Temblor web app to determine the estimated cost and financial benefit of a retrofit for your home. Then, subtract $3,000 from the cost and see whether the net financial benefit is attractive. If your retrofit requires an engineer because the cripple walls are more than 4’ high or your home is on a steep slope, our retrofit estimate might be low. Further, retrofit costs more in the San Francisco Bay area than in greater Los Angeles because of labor rates.
Ross Stein and Volkan Sevilgen, Temblor
Data from Earthquake Brace+Bolt, and the California Earthquake Authority. We are grateful for conversations with Sheri Aguirre, Janiele Maffei, and Margaret Vinci.
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