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Re: Borate-treated foundation sills instead of Stainless Steel

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The last time I checked (a couple of years ago) borate was a special order. Now the yards I've called stock it--in Hem Fir. I guess I should recheck my allowables & spec it. It is the right thing to do.

As for bodies, I was referring to corrosion of sill plate AB  &/or SW nails.  I don't doubt that exposed fastners are corroding--but has anyone seen it in sills?
Chuck
ps The JLC is a great site.

Thor Matteson wrote:
  
Around here the borate treated wood is Hem-Fir, so the allowables will
be down some from D.F. values.  I haven't seen any "bodies" so I'm still
a little skepical. Was it in the JLC forum?
Chuck Utzman,PE
    
Chuck,

I believe that Hem-Fir is used for the OTHER treatments, too, unless special
ordered (rarely have I seen contractors special order stuff, even when I
note it on plans AND give them phone numbers.....).  The borate people
contend that the water-borne borates penetrate all the way through Doug Fir,
so it 'should' actually be easier to find borate treated DF than DF treated
with ACZA, CC, ACQ, etc.  I will try to remember to visit my local lumber
yard and see what species their non-borate PT stock is.  As I recall, it's
Hem-Fir....

As for the "source", yes,  the comments I referred to were on the JLC forums
(great place for bored SE's-- www.jlconline.com , then click 'forums' on the
menu --'building science' and 'rough framing' can be very educational,
entertaining, and frightening at the same time...).  It's been a couple of
years since those posts, at least.  About 10 years prior to that, when ACZA
was 'new'  in California, a contractor/friend called me and mentioned a
sheet-metal post cap was disintigrating into a pile of white powder after
six months of contact with some ACZA-treated wood.  We tend to generalize
about contractors as only being interested in the structure standing up
until their one-year warranty period is up.  So when THEY start worrying
about this sort of thing, it scares me....

Where are the bodies?  Well--how many earthquakes have we had since 2004,
when this stuff went into widespread use?  Perhaps it would be more
pertinent to consider that maybe it does take a few years for anchor bolts
to corrode away in the new PT wood.  So ten years from now if an earthqake
slides a bunch of houses off their foundations, we will have proof there's a
problem.  Rather than take that risk, I will simply call for foundation
sills of borate treated wood, which is cheaper, safer for humans to work
with, and lets me sleep at night.

I see no reason to use copper-based preservative treatments when borates
offer the same preservative qualities without the bad side effects.  I don't
see why skepticism should even enter the picture.  You have two product
classes available, both of which prevent decay/infestation, and both (should
be) available in Doug Fir.  One of those product classes may cause your
anchor bolts, framing clips, shear panel nailing, etc. to corrode to some
degree.  Which product do you choose?  Pleeeeeeeze tell me that it will be
borates from now on.....

Thor
www.shearwalls.com


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