Cathedral ceiling insulation
I had posted a previous question regarding insulating a new construction vaulted ceiling (2×12 raftered) in Michigan (zone 5). Exterior roof is standing seam metal roofing over osb covered with ice & water shield. There is no exterior insulation, due to our poor planning.
From piecing together your and Dana’s previous recommendations we have decided to make this roof “hot” using 5.5″ closed cell foam sprayed directly to underside of osb sheathing. We will fill the remaining ceiling cavity with R-23 rockwool (5.5″) and covered with 1/2″ drywall.
I have deduced from reading many of your recommendations that we should NOT install a vapor barrier below the rockwool. Is this correct? Do we need any kind of vapor retarder, either a film or in the paint? Do you see any problems with our plan?
Thank you for your help!