Should I use a poly-type Membrain sheet or vapor retarder paint for ceiling?
I’m at a crossroads with how to deal with the ceiling vapor retarder in my new construction home in climate zone 5.
I’m prepping for drywall, and am wondering if I should apply Certainteed Membrain vapor barrier to the underside of the studs on the ceiling, and then just have the ceiling drywall screw attached…
Should I have the ceiling drywall glued and screwed and use vapor retarder paint instead.
I plan on blowing R60 cellulose in the attic when done, and am concerned about it’s weight on the drywall.
Most drywall installers I’ve talked to advise against using glue. For one it adds more cost, and it will also be difficult to repair any damages in the future.
I’ve seen Bill Hulstrunk’s comment about successful experience of adding R100 to the ceiling without any sagging issues, but I wonder if he was just screwing, or using glue as well?
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What is the spacing on your rafters, and the thickness of your drywall?
A similar questions was discussed in this thread: https://www.greenbuildingadvisor.com/community/forum/green-building-techniques/25580/58-drywall-sufficient-support-r-60-cellulose-ceiling
In zone 5 there is no need for a ceiling vapor retarder with a vented attic design. Air tightness still matters though.
Using ring shank nails for the gypsum board is usually enough for managing the weight of deeper cellulose than R60, no need for glue. If it's a 24" o.c. truss design rather than 16" o.c. joists, install 1x strapping 16" o.c. perpendicular to the truss chords with screws or ring shank nails (shimmed for ceiling flatness), and ring-shank the gypsum to the strapping.