We seem to be having a fair bit of cold penetration along the basement
mudsill (above the stone foundation) and between the floor joists.
I would like to insulate and my first thought is to use a combination
of the 2 inch "pink" rigid insulation (cut to size) plus expanding
foam insulation to fill remaining irregular gaps.
Any other or better suggestions before I start the project?
The ideas you have sound OK. Since the draft is coming in through the
floor jouist I would consider getting up there with come regular caulk
and seal all the cracks where the cold can come in. Foam is only
needed for really big cracks.
At that point you could just use fiberglass bats which are
conveniently sized to fit in the space between the joists. It would
require some type of ceiling to finish however, drywall perhaps. A
finished basment adds to the function and value of the home and
finishing the ceiling is a big step in that direction.
Perhaps my explanation is unclear. The area of cold is along the
outside *perimeter* of the house at the level of the "mudsill" which
in my old house is something like a 4x10 or so resting (irregularly)
on top of a 12 inch or more stone foundation. My guess is that a lot
of the air is leaking between the inevitable cracks between the
irregular foundation and the mudsill. But additional cold is probably
penetrating the mudsill itself since wood has a rather poor R-value.
So I was proposing to cut (irregular) rectangles of 2" pink rigid
insulation to fit between the joists along the perimeter mudsill. Then
since everything is rather irregular anyway I was going to use foam to
seal between the rigid foam and the surrounding joists, stone
foundation and mudsill.
Does this explanation help?
I would love to just foam it but I am worried about two problems.
1. The spray cannisters they sell (at least at home centers) are
rather expensive. Say $7-8 per aerosol can (even the pro-pack stuff
is not much cheaper)
2. It tends to look rather messy and non-professional -- and I don't
think it is just my application technique :)
Do you have any specific suggestions on materials or techniques that
might avoid the abvoe two problems.
They sell the stuff in, not aeresol cans, but in multigallon
cannisters, (two components and some mixing apparatii (apparatae?)
And if it's an unihabbitted space, it doesn't really matter
how uprofessional it looks, and if its' inhabbited, you're
supposed to cover it. In any case, once it's up, you can
carve it to shape with an electric carving knife.
Oh, you mean the REAL stuff :)
Do you know whether you can rent the mixing apparatus for a reasonable
price since I am only doing a small area so no real interest in
spending big $$$ for whole-house sized equipment.
I know they sell expensive special purpose ones, but again can you
either rent or get some reasonably good low-cost alternative.
Are you doing this repair from the inside? If so, I did exactly what you
are proposing. The only difference is that I put a good size bead of
caulking on all four seams of the space and smushed the poly board into it.
A more recent example is to cut the foam a bit smaller then the opening
leaving say about a half inch gap all around and then going back with the
spray foam to fill in the voids. Much easier then trying to get tight fits
with the foam board.
I'm guessing as long as you aren't using the fiber glass to stop
drafts. I've learned from my house, that I can insulate the heck out
of something, but drafts will make areas still feel cold.
For the foam stuff, I like the dap latex stuff. It cleans up well.
tom @ www.BlankHelp.com
I prefer Icynene insulation around sil interior
the R-value is much higher than fiberglass.
| >We seem to be having a fair bit of cold penetration along the
| >mudsill (above the stone foundation) and between the floor joists.
| >I would like to insulate and my first thought is to use a combination
| >of the 2 inch "pink" rigid insulation (cut to size) plus expanding
| >foam insulation to fill remaining irregular gaps.
| >Any other or better suggestions before I start the project?
| I'm guessing as long as you aren't using the fiber glass to stop
| drafts. I've learned from my house, that I can insulate the heck out
| of something, but drafts will make areas still feel cold.
| For the foam stuff, I like the dap latex stuff. It cleans up well.
| tom @ www.BlankHelp.com
I read some where in the irc, that it cannot be exposed. That it can
be used as an exterior sheathing(coverd with a weather proofing
material), but anything inside the home requires a fire barier.
I can't remember where, but I'll look. If anyone else knows the
limitations for interior use please post.
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