Tongue and Groove Ceiling w/ 6mil VB - Wrong?
I am building a bonus room over my garage... above the room is attic space with no current insulation. I have already installed a 6 mil vapor barrier to the joists and then put up the tongue and groove beadboard ceiling. I plan on blowing in R49 fiberglass insulation in the attic. I'm in Nashville, TN.
Will this be adequate to prevent mold and moisture issues in the attic? What about efficiency?
I did not want to put drywall between the joists and the ceiling panels since the overall ceiling is rather low and every 3/4" matters significantly.
Please let me know of any concerns... I would hate to have to tear the ceiling down after spending so much time and money on it, but I don't want moisture or mold problems either.
Re: Tongue and Groove Ceiling w/ 6mil VB - Wrong?
Your post is a little confusing.
If you joists are exposed to the room, the bead board is on top of the joists and the plastic above that and fiberglass above that, then as long as the attic is ventilated, this will work.
If the plastic was attached to the bottom of the joists and the bead board below that and insulation between and above the joists, again OK.
If you are asking if you should have attached sheetrock to the joist before attaching the bead board, no, sheetrock is not needed. It might help dampen any sound transmission between the attic and the room, but all that fiberglass will take care of most of that.
Now if you put the bead board up first and drapped the VB over the tops of the joists and down the sides, that might be an issue.