Around here (northern climate) only 6 mil poly film is considered legal
vapor barrier, kraft faced insulation is useless except to hold the
insulation in place.

"CB" wrote in message
...
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.