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RE: Plywood shear walls with 3x sills...

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After seeing more and more crappy 2x foundation grade sill plate material
that is readily available, of late, seeing more and more 4x or 3x
PT sill plates in actual use, regardless of what the contractors say about
availability...I think that foundation sill plates in zone 3 and 4 should be
3x or 4x regardless of load. Also I think that 3" edge nailing should
require a 4x even if it is not at an *adjoining* panel edge. One nice thing
about some of the pre-1930's bay area wood structures was that they had nice
beefy sill plates. I am watching some of the new lofts going up in San
Francisco and I see double walls with 3x and 4x studs at 16 "o.c. Maybe
that's why its not available, its all being used up in SF.

Jeff Smith

> -----Original Message-----
> From: Peder and/or Cathy Golberg [mailto:golberg(--nospam--at)]
> Sent: Friday, December 03, 1999 10:31 PM
> To: seaint(--nospam--at)
> Subject: Re: Plywood shear walls with 3x sills...
> >
> >
> >3.  I've had some contractors whine (no...really?) about this,
> saying that
> >they either cannot get 3x pressure-treated members or they are very
> >expensive. Some building officials also are not enforcing this
> >(no...really?). Anyone run across this?
> >
> >
> >Dave K. Adams, S.E.
> I'm going through this right now at the moment also, including the whine
> part.  Based on the added weight??, cost, material availability, etc, the
> contractor has pleaded with me to use 2-2x members instead of the
> 3x or 4x.
>  He has gone and recieved approval from the building department to do this
> as long as he can show a letter from the EOR (me) it is okay.  At
> the panel
> joints, I have agreed to allow multiple studs joined with the same nailing
> as the plywood panel edges (studs built-up with 10d at 2" o/c staggered,
> e.g. 2 rows of 4" o/c) as I don't see this any different than shear
> transfer at a typical top plate on a wall that had 10d at 4" o/c edge
> nailing.  I told the contractor I thought they were crazy with the added
> labor and materials and that the 3x or 4x had to be cheaper in the "big
> picture" than his proposed method (penny wise, pound foolish?).
> Apparently
> it is cheaper as the 2-2x is still their desired plan.  The only thing I
> can figure is that the framers don't know the panel edge locations until
> later and think they can add the 2nd stud after the wall is erected.  I
> think this will be interesting to observe during construction.
> I have, however, not given into using 2-2x plates at the sill.  They want
> to use a P.T. 2x with a 2nd 2x nailed on top (2 rows of 10d at 4"
> o/c) with
> the anchors extending through both plates.  I seem to remember seeing
> failures of the A.B. pulling through 2x plates which has something to do
> with the 3x requirement.  I'm not totally sure if I'm being
> consistent with
> my reasoning.
> Any thoughts on using built-up 2-2x members instead of the 3x member??
> Sincerly,
> Peder Golberg, P.E.
> Portland, OR