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Re: WOOD - Engineered Lumber vs. Sawn Lumber

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This makes it tough to frame a wall over a beam with a crown in it.

Bill Allen

> From: Kevin McCune <kmccune(--nospam--at)>
> To: seaoc(--nospam--at)
> Subject: Re: WOOD - Engineered Lumber vs. Sawn Lumber
> Date: Thursday, September 11, 1997 8:33 AM
> I believe that the "extra" 0.5 in 1.5*DL camber for G-Lam beams is to 
> account for long term creep.  This would apply to roof or floor beams. 
> Breyer's textbook third edition p.33 or NDS 3.5.2.  Note that if you want

> to calculate the total deflection of seasoned lumber you should use
> also.  The recommended factor for green lumber 2.0*DL!
> Kevin McCune
> >I'm not sure how to explain this. If you camber the beam for 1.0*DL
> >deflection then, theoretically, when the dead loads are applied the beam
> >will be level. If you camber the beam for 1.5*DL deflection, after the 
> dead
> >loads are applied the beam will still have a negative deflection
> >or "crown" equal to 0.5*DL deflection. Right?
> >
> >Regards,
> >Bill Allen