I'm not sure if I should put plastic vapor seal against the block wall.
It will be a 2x4 wall about an inch away from the block wall. The
insulation will have the standard paper vapor seal/barrier. I know I've
read about problems with 2 vapor seals trapping moisture between the two
and am wondering if this is one of those situations. The garage will be
heated and cooled at times.

I'm also thinking of putting up the sheathing type 4x8 sheets of
insulation and putting the 2x4 wall and fiberglass insulation right
against that. Electrical wiring is of no or little concern here, I got
that part covered.

On Thu, 14 Jan 2010 21:39:42 -0500, Tony
wrote:

I'm not sure if I should put plastic vapor seal against the block wall.
It will be a 2x4 wall about an inch away from the block wall. The
insulation will have the standard paper vapor seal/barrier. I know I've
read about problems with 2 vapor seals trapping moisture between the two
and am wondering if this is one of those situations. The garage will be
heated and cooled at times.

I'm also thinking of putting up the sheathing type 4x8 sheets of
insulation and putting the 2x4 wall and fiberglass insulation right
against that. Electrical wiring is of no or little concern here, I got
that part covered.

Use the foam insulation board against the block wall, then stud and
insulate with Roxul Rock Wool insulation with no vapour barrier. You
need to let that wall breath, and you want insulation that is not
harmed by moisture and that does not support mold growth. That kinda
rules out fiberglass - particularly with paper backed vapour barrier.

That rockwool batting is WONDERFUL stuff.