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RE: Wood Framing - Upgrade or Not

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At 05:09 PM 10/27/98 -0800, Dennis wrote:

I have discussed it with the
>own, his wife and the designer at the same meeting. I told them that the
>home (they just purchased it)was laterally supported by stucco walls only. I
>suspect that the home is governed by wind loads, but portions of the new
>addition will govern by seismic loads.
>Let's see what other comments come in.
As was noted, the code only requires that the addition not make things
worse. You seem to have that part under control. The Bldg Official's
interpretation does not require any separate upgrade. It would therefore
appear that the public interest is satisfied, which leaves the question of
upgrading as a private matter between you and the owners.

I encounter this issue fairly often, and I recommend what I think is a
useful array of upgrades to correct the worst of the Achilles' heel
deficiencies. remember that UBC is not a code dealing with upgrade of
existing buildings, the UCBC is, and it makes concessions to the nature of
the situation. And again, the owner is boss of what, if anything, is to be
done. You are the expert however, and the quality of your advice to your
"consumer" client is what you can be judged on. Let your "care" be to a
reputatable, solidly professional standard. Your inquiry about this matter
has the purpose of better establishing what such a standard looks like.

You already have a strong sense of the inadequacy of this existing
construction for seismic resistance in your area. Tell them what you've told
us in past postings. They're your professional opinions, and they are reputable.

Now for my opinions: Whether wind controls or not, seismic is the real risk.
Walls fail long before 2x roof decks do. You can replace lots of half-inch
interior gypsum board with 15/32 inch OSB or 1/2 inch MDO -faced plywood
that can be finished like drywall without thickening the wall up. You can
epoxy dowel the mudsills to the slab for sliding resistance and secure the
nuts with plate washers.  At exterior and bearing walls you can add nail-on
or screw-on holdowns to numerous studs and edge nail to all of them. Etc.
etc. Leave the stucco as is; shear the interior faces. Recommend enough to
feel good about, and don't worry about satisfying the worst of the seismic
bluenose perfectionists, because it can't be done and its none of their
business anyway. 

Charles O. Greenlaw, SE      Sacramento CA

PS: Bruce Resnick's posting came in and I agree completely. Josh Matthews
has a good point on sale disclosure. Again, recommend an upgrade that
discloses as a positive accomplishment. It could be the best house in the
neighborhood for seismic resistance. Even the best bagels have a residual
deficiency: the hole. Yet bagel makers are accomodated about this.