Home Retrofitting

The Seismic Safety Zone

Home Retrofitting

Homes in California built prior to 1950 were not required to have retrofitting during construction. Retrofitting simply means two protective phases in securing a home against shifting during a quake. The first part, which is necessary, is to have retro bolts installed between the frame sill plate and the foundation of the home. The second part is placing plywood on the lower uncovered walls in two story homes. These are called "shear walls." It adds reinforcement against swaying during an earthquake.

If you have an older home and don't know if it is retrofitted you will need to go under the crawl space of the home and look for bolts every 16 inches along the sill plate. If they are not present, they can be installed by your or a contractor.

The expense primarily depends on the size of the home and whether its a single story or multiple story home. To retrofit the home yourself, you'll need to rent a power drill that will drill through cement and purchase the retro bolts at your local hardware store. Then you can call for several estimates from licensed contractors and compare prices.

Retrofitting is an absolute must in earthquake country. Without the retrofit you home can shift off the foundation. During this process fires easily ensue from broken gas lines, water pipes break and create additional damage and the property inside the home takes a severe beating. Depending on the magnitude of the earthquake and the shift that takes place, without retrofitting, loss of life or serious injury could result.

In most cases the cost of retrofitting could be equal to adding a deck on the back of your home. Not cost prohibitive, but a wise investment in protection of life and property.


	The Seismic Safety Zone Home Retrofitting Homes in California built prior to 1950 were not required to have retrofitting during construction. Retrofitting simply means two protective phases in securing a home against shifting during a quake. The first part, which is necessary, is to have retro bolts installed between the frame sill plate and the foundation of the home. The second part is placing plywood on the lower uncovered walls in two story homes. These are called "shear walls." It adds reinforcement against swaying during an earthquake. If you have an older home and don't know if it is retrofitted you will need to go under the crawl space of the home and look for bolts every 16 inches along the sill plate. If they are not present, they can be installed by your or a contractor. The expense primarily depends on the size of the home and whether its a single story or multiple story home. To retrofit the home yourself, you'll need to rent a power drill that will drill through cement and purchase the retro bolts at your local hardware store. Then you can call for several estimates from licensed contractors and compare prices. Retrofitting is an absolute must in earthquake country. Without the retrofit you home can shift off the foundation. During this process fires easily ensue from broken gas lines, water pipes break and create additional damage and the property inside the home takes a severe beating. Depending on the magnitude of the earthquake and the shift that takes place, without retrofitting, loss of life or serious injury could result. In most cases the cost of retrofitting could be equal to adding a deck on the back of your home. Not cost prohibitive, but a wise investment in protection of life and property. \| home \| Hazard Awareness \| Don's Corner \| Feature Of The Month - Loma Prieta Quake \| Fault Of The Month \| Useful Links \| Earthquake Prediction \| Home Retrofitting \| Earthquake Insurance \| Poem Of The Month \| Field Trip Story \| Professional Insurance Services