Asked Questions by Owners of Single-Family Homes
is retrofitting? I have read that some of the retrofits in the Bay
Area have not been done properly. What should I check for?
most single-family homes involves strengtheing the walls of the
crawl space under your home and making sure that it is attached
to the foundation (with bolts or anchors) and to the floor framing
above. While many homes continue to be retrofitted, we have become
increasingly concerned about the quality of retrofits, including
the workmanship and the work actually performed. Somewhere between
25% and 75% of currently retrofitted homes need additional work.
Make sure that your contractor addresses all three of the following:
1. The mudsill-foundation
connection - Adding bolts and washer plates will prevent the
house from slipping off the foundation.
2. The cripple
wall - Adding plywood panels on all four walls will prevent
collapse of the outside wall of your crawl space (the cripple wall)
to resist collapse, or "shear."
3. The cripple
wall-floor framing connection - Adding framing clips to attach
the plywood shear walls to the floor framing above.
on how to do a retrofit (including the kind and number of bolts,
feet of plywood, types of nails to use, and number of anchors) are
contained in the model "retrofit
A qualified engineer
or other design professional is usually needed to evaluate larger
split-level or two-story homes.
I do any of this work myself?
homeowners who have done other home improvements can do it themselves.
If you plan to do the work yourself, you need to take a training
class. Two classes are open to ALL Bay Area residents.
1 - The Building Education Center in Berkeley 510/525-7610
2 - City of San Leandro Building Department 510/577-3405
Remember that the area under your house can be an unpleasant work
do I find an experienced contractor?
a list of contractors with retrofit training, such as the list on
Ask for two design professional references (architects or engineers),
as well as for two homeowners who have used his/her services.
I need to hire an engineer or other design professional?
you need to hire a design professional, such as an engineer or architect
specializing in seismic retrofitting, particularly if your home is
more than one story (even if the home is only a split level), has
a bedroom or other living area over a garage, or is on a steep hillside.
The engineer will charge $1,000 to $5,000, depending on the complexity
of the job.
do I select the engineer or design professional?
engineer should be a licensed civil or structural engineer with experience
in designing retrofits for homes. A good design professional will
not add unnecessary strengthening and will add the strength where
it is least expensive for the contractor to install. In addition,
some architects may have the expertise to design a retrofit.
I need a building permit from the city or county?
permits are required by law. When you obtain a building permit, you
also have some assurance that the work will be completed correctly.
You really need that permit to protect your investment.
much do permits cost?
cities and counties charge very little for these permits. However,
some cities do not charge at all. A typical permit costs about $250.
Call your city.
much will this cost me?
costs vary, the typical home retrofit that does not require an engineer
costs about $4,500. A lot can be done for $2,500.
can I get the money to pay for this?
equity loans are available from banks. A five-year loan from a bank
for $5,000 for 5 years at 9% will cost you about $104 a month, far
less than putting this home strengthening on your credit card. Homeowners
with low fixed incomes may be able to get help in paying for the work
from their city or county or from the California Department of Insurance.