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

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I haven't had a problem locally, but I think some of the problems has to do
with the building industry coming up to speed on the new code provisions.
Inasmuch as they are on the tail end of this code provision, most of the
demand for 3x framing is probably just starting to become a serious matter.
I would suspect that as demand grows so will supply.


-----Original Message-----
From: Robert Shaffer [mailto:rkdn(--nospam--at)]
Sent: Saturday, December 04, 1999 11:54 AM
To: seaint(--nospam--at)
Subject: Re: Plywood shear walls with 3x sills...

As a builder as well as an engineer,  there are certainly some logistics
problems associated with 3x materials.  I performed a random survey of 3
yards.   One I deal with regularly and two others in the San Jose Area and
these are the results of my mini survey:

Did they have 3x4 in stock?   All three said no,  but one of the yards
to run it immediately for me.

How soon could I get a Unit of 3x4 ?   All three cold have a unit delivered
my job in three working days.

How much for a Unit of 3x4 ?  None would give me a solid quote until they
with the Mill,  however when I pushed a little I was told by one yard that
would be around $  600.00 per MBF ( 2x4 was quoted @ $ 480.00 )  That
to a 25% cost increase for the few 3x members which may be required.

I know that 3x pressure treated is stocked by most commercial lumber yards
it was quoted @  $ 1150.00 MBF.   Expensive,  but typically not much is

>From a buildability standpoint,  the 3x stud makes layout more challenging,
increases is the weight of the wall you have to lift and adds one more thing
the growing list components that need to be purchased.  All of these I see
more of a nuisance than real problem.

A 3x sole plate for a stud wall is a little tougher,  I have not seen 30d
for a pneumatic nailer,  so the sole is going to be hand nailed from the
or toe nailed.   I can see this as real a problem for the production framers
big tracts,  but does not have a huge impact on custom residential.  I have
always used 3x p.t. for mud sills and ledgers.

So, IMO,  tell the contractor to stop whining about it and get on the lumber
yards to stock 3x .  Careful detailing to avoid abutting plywood panel edge
nailing of the walls will reduce the amount of 3x required as well.

Robert Shaffer, P.E.
Santa Cruz,  CA

Peder and/or Cathy Golberg wrote:

> >
> >
> >3.  I've had some contractors whine (no...really?) about this, saying
> >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
>  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
> 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?).
> 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)
> 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
> my reasoning.
> Any thoughts on using built-up 2-2x members instead of the 3x member??
> Sincerly,
> Peder Golberg, P.E.
> Portland, OR