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Re: WOOD - Engineered Lumber vs. Sawn Lumber

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Hypothetical question:

Suppose you have a 16'-0" garage door.  Above the garage is a bedroom.
You used engineered lumber throughout the floor framing.  (TJI's, LVL's,
etc.)   You have allot of trib area for dead load and live load.  You
put the dead load and creep camber in the garage door header.  There is
a short stud wall above the header which supports the floor framing.

Does the carpenter reflect the camber in his stud wall and bedroom floor
to account for creep?  If so how much?  (Keep in mind that all of the
dead load is not present until the upper wall supporting the roof has
been placed.)  Do you have a bow in the floor until the creep makes it
flat?  Or do you bolt nailers on a wide flange steel beam and go home
early and get some sleep?

Corollary question:
How do you calculate the creep of a flitch plated beam?  Base it on the
initial relative stiffnesses of the components?

Most framing crews I know make the floors dead level as they build them.
 This means when you add the additional roof dead load from the bearing
wall and when it creeps you will have a dip in the floor.

Harold Sprague
Black & Veatch

From: Dennis S. Wish PE
To: seaoc(--nospam--at)
Subject: Re: WOOD - Engineered Lumber vs. Sawn Lumber
Date: Friday, September 12, 1997 2:33PM

 -----Original Message-----
From: Bill Allen, S.E. @ ALLEN DESIGNS <BAllenSE(--nospam--at)>
To: seaoc(--nospam--at) <seaoc(--nospam--at)>
Date: Thursday, September 11, 1997 4:09 PM
Subject: Re: WOOD - Engineered Lumber vs. Sawn Lumber

>1. Try building a wall on a beam with a crown on it. I've gotten a lot of
>complaints from framers with regards to beams of "excessive" camber.
>2. Sawn sections don't have this provision.
>Bill Allen

Bill, I'd much rather have the contractor who is frustrated trying to
a wall above a camber, rather than have the client take me to court
of too much deflection.