Quote:
Originally Posted by Sliver
Seems pretty expensive for a really low R value. I think $45 in fiberglass insulation will be better as I'll have a higher R value and it'll be a fraction of the price, but just not sure if I need a vapor barrier. I think the vapor barrier is just for outside walls so I should be okay, but I'm not certain. There could be a five degree difference in temperature above the insulation versus below. Is that a factor or a non-issue?
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You don't need the vapour barrier. Even if you were to put a vapour barrier in, it would have to be on the warm side of the insulation which is difficult to do between joists, and your subfloor is performing as a pseudo vapour barrier anyways.
Unless you're storing dead dogs in there, in which you might want the spray foam to keep the smell down.