California
is a land of earthquakes. Scientists believe that California
has entered a period of increased seismic activity. Since
1989, California has suffered four magnitude 7
earthquakes, more are sure to follow.
"Many of the homes in Los Angeles were built
using older construction techniques which are inadequate for the
forces we now know earthquakes can cause; but, these older homes
can be reinforced easily and inexpensively." (LA
Dept. of Building and Safety)
Reports
of recent California earthquakes
Index map of recent
earthquakes in California
Faults of Southern
California
What
is seismic retrofit?
Seismic
retrofit strengthens the connections between a house and its foundation
using specialized hardware and engineering methods. In the
event of an earthquake, it reinforces the structure of the house,
reduces and in some cases, prevents structural damages to the house.
Check
the Seismic Retrofit Info web page for additional information.
Reasons
for retrofitting
-
Earthquake
insurance typically carries a 20% deductible. Retrofitting
helps to reduce earthquake damages, hence it is worth much more
than its cost.
-
Homeowners
want to ensure the safety of their family.
-
Landlords
want to avoid future loss of income from a vacant and damaged
building.
-
Some
earthquake and homeowner's insurance require house retrofitting.
-
Proper
disclosure about foundations are required before property transfers.
What
kind of house needs retrofitting?
California
Government Code Section 8897 says,
"... there are approximately 1,200,000 homes
in the State of California which may not be bolted or anchored to
their foundations or do not have adequate cripple wall bracing."
"Homes
built prior to 1940 in Los Angeles were built without being bolted
to their foundations. Without this anchorage, a large earthquake
can move the ground and the foundation right out from under the
house. Older homes were damaged or destroyed in this manner
by every major earthquake in California's history."
(LA
Dept. of Building and Safety)
"Some
wood frame homes built as recently as the 1970's were shaken off
their foundations in recent earthquakes. Even though these
modern homes were bolted down, they failed because of weak bracing
materials on the cripple walls. ...The cripple wall must be
braced with Ber materials like plywood. If not, the next earthquake
may damage the cripple wall and move your home off its foundation,
even if you've bolted it down."
(LA
Dept. of Building and Safety)
It
is best to have a licensed contractor or inspector check your foundation
and cripple walls, make sure they are secured and up to the current
building code.
How
much does seismic retrofitting cost?
The
cost of retrofit varies. Typically retrofit done on a single-family
home by us costs between $1,000 to $3,000, which is well within
range of estimates by LA Dept. of Building and Safety.
California
Dept. of Insurance offers low interest loan and grant program to
qualified homeowners, please check the retrofit grants web page.
