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Re: GBlist: Dangers of CCA Pressure Treated Wood



What a coincidence I'm covered head to toe in red cedar dust and if I
can stop sneezing long enough I could put in my two cents

Waste from milling and processing of cedar and similar woods is as Terry
implies and my skin testifies a toxic material and in areas like this
with a hundred years of backwood sawmills there is a fair amount of
evidence of soil and groundwater contamination. I guess the point I'm
making is that the use of a naturally decay resistant species is not
without potential environmental cost that might be comparable to or
exceed the env. cost of a copper based treatment depending on the
process. I don't know. 
Another question that comes up is effectiveness. Decay resistant is not
rot proof and estimates of longevity of naturally decay resistant wood
start at 20 years but the problem here is that the source of material
that has been discussed here i.e. quick growing (weeds?) tends to be
high in sapwood, have little structural integrity and quickly prone to
decay unlike an older growth version of the same species which you
really don't want to use for that purpose. You would get longer
protection for a deck if you left the tree standing and built the deck
under its canopy.

I guess my basic opinion on the whole question of wood preservatives is
one of avoidance in other words that the only wood that should be near
the ground or in a moist situation should have its roots intact. I can't
think of any building application that should require the use of
pressure treated wood to maintain integrity - there is always a design
alternative and that alternative shouldn't consist of finding an
environmentally appropriate way of making wood decay resistant. 

I'm not a fan of uncovered decks (I always thought them expressive of
some fear of being close to the ground) but a wooden deck properly built
using heartwood planks oriented properly and UNFINISHED should outlast
its purpose.

John

TBren46501@aol.com wrote:
> 
> In a message dated 6/9/97 3:55:34 PM, crkoehn@mailbag.com (Chris &
> Ruth
> Koehn) wrote:
> 
> <<We've been considering using some of the  native and naturally rot
> resistant wood species in place of cca treated wood.  My forestry
> connections suggest that walnut, certain species of locust, red cedar,
> and katalpa are all very rot resistent- in some circumstances as much
> so
> as cca treated wood (my father in law used locust for fence posts on
> his
> farm, which have been in ground contact for 50 years and still look
> good). In many instances logs can be had for the trouble of removal
> here
> in Wisconsin. Most of these trees are extremely invasive, and
> considered
> "weeds" by farmers and woodlot owners.
> 
> Any experiences with these materials? I know it's a hassle cutting and
> sawing and drying.
> 
> How about using this ACQ preserve stuff? Anybody tried it?
> 
> Chris Koehn
> Top Ridge Homes>>
> 
> Hi Chris,
> 
> Yep.  My experience with white locust, arborvitae, red cedar, redwood
> and
> cypress is that they are extremely well protected from fungal
> breakdown and
> insect infestation.  I'd like to see programs that grow, transport,
> machine,
> transport and eventually dispose of them managed in ways that minimize
> impact.  Here's my "yesbuts".  None of these trees are weeds. I don't
> know if
> any of them are being managed as a renewable resource.  I'd like to
> hear from
> the eco-foresters on that one.  Last I knew, cypress was a species at
> risk
> (too bad cause it lasts the best).  Working these woods without
> respiratory
> protection will expose you to the natural toxins present in every one
> of
> them.  My old partner and I ended up at the emergency room with toxic
> shock
> after three days of working with black walnut.  Lastly, locust is damn
> bear
> to saw, plane or sand - a tool eater.  - Terry
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