You do need a vapor barrier. I also would say you need ventilation.
As an alternative, you could have the back of the roofing sprayed with closed cell polyurethane insulation.
Todd Miller
2007-12-30 22:55:05.000000
I have two room aditions one 12x19 the roof is aluminum pans 6" below I have a drop ceiling. I have had a condensation problem. Recently I insulated and vented I did not put plastic up but the insulation has a vapor barrer on it.Should I put 4 mill plastic between the drop ceiling and the insulation? the other room I have is the same build but it is 25x25 with a closet and utility room built on one side with a full wall seperating them the smaller the room the less condensation builds i am wanting to insulste this room as well what would be the best procedure any help would be great. Thank you.
