Asking an Earthquake Retrofit Contractor the Right Questions

Homeowners often think an earthquake retrofit is simple.  After all, what could be so hard about being an earthquake retrofit contractor when all you do is put in bolts and nailing up plywood?   Actually, it is not that simple. This New York Times article, as well as this CBS News Report, ran exposés on how specialized it is. This is a consequence of not having a retrofit building code .

Without a doubt, the earthquake will let you know if you hired the wrong seismic retrofit contractor.

 

Questions to ask an earthquake retrofit contractor

Does He Know About These Guidelines?  If not, he hasn’t done his home work.

The Bay Area’s regional retrofit standard  “Standard Plan A”

California’s retrofit guideline “Appendix Chapter A3”

Seattle’s “Project Impact Retrofit Guidelines”

Los Angeles Department of Building and Safety Standard Plan Number 1

“Earthquake Strengthening of Cripple Walls in Wood Frame Dwellings”.A guideline published by the Federal Emergency Management Agency after the Napa earthquake,

And the most recent FEMA: Vulnerability – Based Seismic Assessment and Retrofit of One and Two-Family Dwellings

The California Historic Building Code\

Does This Earthquake Retrofit Contractor Know About These Research Labs and Testing Facilities?

The American Plywood Association is responsible for shear wall tests in Canada and the United States.

The American Wood Council which published the crucial Special Design Provisions for Wind and Seismic?

The International Staple Nail and Tool Association.  Tells a seismic retrofit contractor everything there is to know about fasteners used in seismic retrofits.

These tests done by the Structural Engineers Association of Southern California in 1992.  They demonstrated  that low quality foundations without steel reinforcing perform quite well in earthquakes.

Other Information Seismic Retrofit Contractors Should Know.

Ask your contractor if he thinks brackets on posts are a good idea.  A lot of them recommend this wasteful procedure.

These tests done by the Structural Engineers Association of Southern California in 1992.  They demonstrated  that low quality foundations without steel reinforcing perform quite well in earthquakes.

Does your earthquake retrofit contractor know about the 4 methods used in building retrofit shear walls?

Is your contractor familiar with old building code provisions that specify the strength of existing structures? If you don’t know how resistant a building already is, you can’t know where to address the weaknesses.  These code provisions are found in Table A4-A of the International Existing Building Code.

How to address brick foundations?  Gudelines for the Seismic Retrofit of Existing Buildings 

The Best Referral Source for Seismic Retrofit Contractors

Professionals such as members of the American Society of Home Inspectors are a good source for referrals. They see retrofits everyday and will know which contractor does quality work.