Flat roof insulation retrofit
What’s the best way to re-insulate this roof in NW Indiana – Zone 5?
Existing low pitched un-vented roof assembly:
EPDM (newer, white.)
1.5″ foam board (Polyiso, I think.)
3/4″ 1×10 decking.
2×12 24″ O.C. wood joist cavity with 1″ crepe paper insulation.
3/8″ drywall.
Drop ceiling grid in some areas also.
I have drywall and old insulation removed and ready to do what I need to do from the underside to make it as efficient and problem free as is practical for relatively long term.
Thanks in advance for any help you can give. I’ve read what I can find here, but I’m still concerned that this is a tricky situation given the exterior that I want to leave as-is if possible or plausible.
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Replies
I would spray foam
2.5-3 inches of closed cell spray foam and fill the rest with batts to get R value you need. This way you get the vapor barrier, impermeable air layer and the r value you need.
Thanks for the reply. What, if any, facing would you recommend we use on the batts? Foil? Kraft facing and put drywall back and paint it?