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Naturally Durable Wood

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Gail Kelley wrote:

"I was thinking specifically of code section 2304.11.22. - wood framing 
memebers which rest on exterior foundation walls and are less than 8 in.
from 
exposed earth.

Are there reasons to use naturally durable wood?  Do they justify what I

assume is an increased cost?

Gail Kelley"


I can think of three good reasons.  The first is that the chemicals they
use to treat wood with are extremely toxic.  The act of treating the
wood exposes workers to toxicity.  The people who live near the plant
are exposed to it.  The carpenter who saws the stuff is exposed to quite
a lot of it, since the fine dust that can get deep into your lungs has
to go past his face first.  And then, someday, the building will be torn
down or burned, and the stuff then goes into our landfills or our air.
Not to sound like a tree hugger, but anybody who says this stuff is
known to be safe has breathed too much of it.  Several of our architects
spec cedar cants and the like and forbid treated wood in their roofs.
I, personally, respect that.

The second reason is that the treatments are done using a water bath.
They take a nice piece of kiln-dried wood, which has only just gotten
used to being dry and started to stabilize; and they completely saturate
it, pat it surface dry, and ship it.  As soon as the lumber yard cuts
the strapping around the bundle, every single piece in it starts to warp
and curl.  And then some carpenter gets to try to frame a straight plumb
wall on top of it.

Lastly, it's corrosive to steel fasteners.  Although, so is white oak if
it's green or continuously wet.

On the other hand, as you said, the stuff is cheap, and it's a lot
easier to drive nails into than white oak or locust.  And, walnut dust
is pretty toxic (I know sawyers who won't touch the stuff), although you
don't see much walnut stick framing, so it's not really an issue.

Mike Hemstad, P.E.

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