Ask the Inspector
No Need to Slide in a 'Quake
I've seen pictures of houses that have slid off of their foundations in an earthquake. How can I prevent that from happening to my home?
In some older homes, the frame is not securely fastened to the foundation. In an earthquake, the house may rock off the foundation, causing major damage.
Since the mid-1970s, San Diego homes have been built with earthquakes in mind. City codes now require that structures be securely bolted to their foundations.
If your house isn't bolted down, we recommend consulting a licensed contractor or engineer to evaluate your home and make any major improvements needed.
One common technique these professionals may use is the retrofit anchor, of which there are two types. Adhesive anchors consist of a capsule inserted into the cement, filled with an adhesive chemical and then secured with the bolt.
A mechanical-wedge anchor is inserted into the cement with a hammer. As the nut is tightened with a wrench, the tapered shaft is pulled up, wedging the clip into the sides of the hole.
The anchor the contractor will use and its eventual performance will depend on the condition of the concrete, the embedment path, the edge distance, spacing between anchors and retrofit conditions unique to your home.
In addition to the foundation, take a look around your house for other things, such as brick chimneys and brick and masonry veneer, and make sure they are properly secured as well.
Depending on the amount of work performed, a permit may be required. Be sure your contractor checks with our department before proceeding.
My water heater seems heavy enough to stand up in an earthquake. Do I really need to secure it?
All new buildings are required, under California State Law, to have their water heaters strapped down. And, when you sell, you now need to clamp the tank. We recommend all water heaters be secured.
There are many products available at your local hardware store to strap down your water heater. Whether it be electrical conduit and bolts for under $1 or a complete stainless steel kit for $17.95, as long as they are properly mounted to a wall stud, they will all be effective.
If left unstrapped or improperly secured, a water heater can be tossed over, destroying it and dumping the water that's inside.
As the water heater falls away from the wall, it may pull the flexible gas line. If the line breaks, dangerous gas leaks will soon follow.
Also of concern is the rupturing of the cold water pipe, which may result in flooding and numerous other problems.
Is there a way to make my home earthquake proof?
Making a home earthquake proof is impossible, but making it earthquake resistant is fairly simple. By securing bookcases, cabinets and their doors, you can prevent injuries and major damages from occurring.
Take a look at your home and see what can fall and where it will land. If it blocks your way out of the house or may fall on a person in bed, secure it.
By installing positive catching latches to cabinets, you can ensure they will not swing open. Hardware stores provide many types of these latches.
Keep tall furniture sturdy by attaching it to the studs in your walls with metal "L" brackets. If you have open shelves, affix a guard -- either a wood molding or a metal or wire guard rail will do -- to keep objects from sliding off. Also, place the heavier items on the lower shelves.
Pictures hung on nails will more than likely come crashing down in an earthquake. To keep them from falling, hang them with "close" hooks screwed into studs or ceiling joists only.
Remember, there's no way to be completely earthquake proof, but by taking the proper precautions, you can prevent injuries and minimize the damages to your home.