Should I bolt my tri-level house to the foundation?
I have a tri-level house in the Seattle area, built in 1971. I don't believe it's bolted to the foundation. Half of the house (the side with two floors) sits on top of a slab. The other side of the house is on a standard foundation that I have easy access to, the storage space underneath has a 7' ceiling. I'm wondering if I should look into bolting the non-slab side of the house to the foundation? Or if the side of the house that sits on slab should be sufficient to hold the other side of the house on the foundation in the event of a big earthquake. Thanks for any help or advice!
Anchoring the house to the foundation is a good idea. Most of the houses damaged in the last San Francisco earthquake had gone through extensive renovations but this important step was skipped. It is the reason many could not be saved. It is relatively inexpensive to do this.