foundation

Wait - Your Inspector Didn't Say Anything About Anchor Bolts?

First, a little history lesson. We tend to think that modern standards are inherently superior to the ‘good old days’. That may be so, but that does not mean that an older foundation is unsafe or needs a full retrofit. Many of our old foundations (in this region) are doing just fine. Many of those do not have a single anchor bolt, either.

Washington State began requiring anchor bolts on a statewide basis in about 1973 though many of our 1950s and 1960s Pullman and Clarkston homes have them. Prior to that, the state mandated them in the Puget Sound region due to earthquake potential.

Anchor bolting is installed to handle seismic and wind forces that have the potential to knock a home off the foundation. The Northridge quake is a case in point. The manner in which we installed them changed after that quake and the design of the washers was modified to limit damage.

Anchor bolts are not always visible - finished basement will prevent access - but it pays to have your inspector making the effort to identity if they are present or not. I do so in my reports on a separate line. If they are missing, the client gets a nice explanatory paragraph.

It’s a fairly common defect to find that the anchor bolts are present but missing washers and nuts. When this happens, it becomes a repair issue. If they are not spaced correctly, it becomes a judgement call - is it worth the cost to retrofit versus the risk. On this side of the state, our earthquake risk is minimal compared to Seattle. Most people don’t retrofit, but they always appreciate the information.