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.
