Re: GBlist: Natural sealants
JBunzick (JBunzick@dprarchitects.com)
Fri, 21 Feb 1997 10:06:48 -0500
Marc
Wow, that's tough one. I think, ironically, that the most natural
caulk is tar, since it is a naturally occurring substance used for
something like 4,000 years. But I don't know whether it would be the
best thing to use if you're trying to avoid odors and carcinogens. Nor
is it likely to be easy to use or effective once in place. One thing
to keep in mind is that caulking is a fairly small amount of material
overall in a building. Is this owner chemically sensitive? or just
trying to use sustainable products? That would be important because
the most effective product against infiltration (saving enery) may not
be the best choice for chemical sensitivity.
Polyurethanes (caulks and other construction products) have been known
to emit certain types of gasses (I think MDI is one) which are claimed
to be harmful, so even though they perform really well, I'd avoid
them. Silicones, I believe, are less "emitting", but I don't have the
facts on that. I would come down in favor of siliconized acrylic
latex, which is fairly odorless and has a little bit of flexibility
(so its not great in joints that move a lot). Its mostly acrylic, I
believe, and is readily available and paintable.
In a new construction project, it would be somewhat easier to build in
such a way as to minimize the need for caulk-in an old building, that
option is pretty much shut out. I think a better, tighter home where
acrylic caulk is used is the more sustainable option versus a leaky
home with none.
Just thinking.
John Bunzick
Dean Architectural Alliance (soon to be at HKT Architects with a new
mail address: bunzick@tiac.net)
______________________________ Reply Separator _________________________________
Subject: GBlist: Natural sealants
Author: Marc.J.Rosenbaum@valley.net (Marc J. Rosenbaum) at Internet
Date: 2/21/97 8:10 AM
I have a building to fix where the owner was fanatical about everything being
natural and non-toxic. The problem is, it is incredibly leaky. What
substances are natural sealants, replacing caulks? Need to accommodate
movement, etc.
Marc
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