Originally Posted by biglurr54
I am putting insulation in an stock that has no vapor barrier. I will be adding a vapor barrier before I add the insulation. I will be adding 8 inches of oily ISO foam that will rest on the attic floor jiosts. I was planning on putting the vapor barrier over the attic floor joists, staple and tape everything. Then I will lay the foam over it. Will this rot out my joists because the moisture will be held there by the vapor barrier.
Can you clear up the words in red?
The iso probably has a facer on it that will be enough vapor retarder. You're probably going to get more bang if you cut the iso to fit between the joists and get it down to the ceiling level. Then you won't have that huge air gap.