Foundation Seismic Retrofitting Needs and Solutions
Foundation seismic retrofitting uses bolts and plates. Bolts are added through the sill, or mudsill, and into the foundation. The sill is the wood that rests flat on top of the foundation, where vertical components are installed. Bolts are added because there may be no existing bolts, or the existing bolts are not adequately installed. They may be weak or spaced too far apart to resist seismic activity. In these situations, expansion bolts and epoxy-set bolts are used.
Expansion foundation bolts are the basic bolt used in retrofitting. They cost less, but they require a good foundation to work well. Homes with newer foundations or foundations in good condition are well suited for these types of bolts.
Epoxy-set foundation bolts work best in older homes due to their weaker foundations. These are usually longer than expansion foundation bolts, and set in an epoxy resin inside the foundation. They also work better for an uplifting forces from an earthquake.
More Benefits to Seismic Retrofitting
Besides the assurance that your home has the maximum structural preparedness a seismic retrofit can offer, you may be eligible for earthquake insurance. You’ll need to ask your insurance agent for confirmation. Another benefit to earthquake retrofitting is that reduced or no damage to your home means little to no waiting on a contractor to repair your home in the lengthy aftermath of an earthquake.