So we're redoing our bathroom and it's out to the studs. It's 2x4
16"-on-center wood frame house. The bathroom is on an outside corner of my house, and so 2 of the 4 walls of the bathroom on the exterior and have insulation. These 2 walls happen to be back and side of the shower. So I'm reading around and seem to be getting different things from different sites on kraft faced insulation, greenboard, cement board, and drywall. (I know to use cement backer board for the shower tile substrate).I have just hung kraft faced insulation, so my question is with greenboard....do I use it in combination with the kraft faced insulation (r13)? Some out there say to not use greenboard if you've already got kraft faced insulation up b/c then there's 2 vapor barriers and the moisture could get trapped in between the layers.
Second question - greenboard on the ceiling or no? Some say it sags.
FWIW - the drywall I took down was 30 yr old normal gypsum board, and the insulation behind it was in decent shape, although poorly installed. The painted walls appeared decent for a 30yr old bathroom, although there was some moisture/drip lines from shower steam.