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 putting in bolts and nailing up plywood?   It is not that simple. This New York Times article, as well as this CBS News Report, reveal how specialized it is. This poor workmanship is a consequence of not having a retrofit building code .

One thing we know for use, the earthquake will let you know if you hired the wrong seismic retrofit contractor.

 

Questions to ask an earthquake retrofit contractor

Does Your Retrofit Contractor Know These Guidelines?

If not, he hasn’t done his homework.

California’s retrofit guideline “Appendix Chapter A3”

Seattle’s “Project Impact Retrofit Guidelines”

Los Angeles Department of Building and Safety Standard Plan Number 1

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

“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-Story Dwellings

The California Historic Building Code\

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

The American Plywood Association tests shear walls (every retrofit has shear walls) 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.

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.