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

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Robert-
If I remember correctly, 3x4 = 1 bf/lf and a 2x4 = 2/3 bf/lf?  So isn't this
really an 87% increase? [(1.0x600)/(0.67x480)=1.87] ;<)
Regards,
Bill Cain
Oakland  CA
	-----Original Message-----
	From:	Robert Shaffer [SMTP:rkdn(--nospam--at)cruzio.com]
	Sent:	Saturday, December 04, 1999 11:54 AM
	To:	seaint(--nospam--at)seaint.org
	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 lumber
	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 offered
	to run it immediately for me.

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

	How much for a Unit of 3x4 ?  None would give me a solid quote until
they spoke
	with the Mill,  however when I pushed a little I was told by one
yard that it
	would be around $  600.00 per MBF ( 2x4 was quoted @ $ 480.00 )
That amounts
	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 and
	it was quoted @  $ 1150.00 MBF.   Expensive,  but typically not much
is
	required.

	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 to
	the growing list components that need to be purchased.  All of these
I see as
	more of a nuisance than real problem.

	A 3x sole plate for a stud wall is a little tougher,  I have not
seen 30d nails
	for a pneumatic nailer,  so the sole is going to be hand nailed from
the bottom
	or toe nailed.   I can see this as real a problem for the production
framers on
	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 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
	>