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GBlist: Questions on concrete sealant & vapor barriers for a below grade living space



Questions on concrete sealant & vapor barriers for a below grade living space:

I have an unfinished basement that I'm finishing in the Boston area.  The
structure is all uninsulated cast concrete.  Its approximately 5 feet below
grade and 2.5 feet above grade.  There doesn't appear to be any foundation
drainage.  The dehumidifier removes approx. 7 gallons of water a day right
now.  I expect the humidity to increase once we start occupying the space.  

My current plan is to tape and seal 6 mil polyethylene across all walls and
the floor slab.  On the walls I was going to use R13 un-faced batts except
for the above grade portion where I can fit R19.  This will be air sealed
from the interior with drywall.  I know the general rule is to put the vapor
barrier (poly of Kraft) on the warm side in heating climates but I think I
should put it on the concrete foundation b/c of all the water that's
currently diffusing through the walls and floor.  Does anyone think this is
especially bad b/c of the 6-7 month heating situation in Boston?  

Also can anyone comment on the benefits or any potential health risks of
applying a concrete water sealant (like Olympic or other commercial
products) to the interior surfaces of the concrete?  If this stuff really
works and isn't going to off gass nasty chemicals into the living space,
then I would either move the polyethylene layer to the interior behind the
drywall OR use Kraft faced batts on the interior and no polyethylene at all.
I guess the poly or Kraft might help keep out the sealant emissions if it
should actually be an issue.  Can anyone offer me some good advice?


Thanks in advance,

Joe Charlson

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