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.

On Jun 3, 1:44*pm, CB wrote:
So we're redoing our bathroom and it's out to the studs.

snip

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.

Yes, greenboard is OK. It is a so-so vapor barrier, but its basic
important property is moisture resistance. Best used with setting type
compounds and fiberglass tapes for best water resistance.

Second question - greenboard on the ceiling or no? *Some say it sags.

Definite NO according to one customer service query years ago at a
major drywall maker. Maybe not as important with some of the newer
types of drywall (mold resistant, etc.) now on the market.

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.

Likely your project will turn out quite well. Good luck.

Joe

On Jun 3, 2:31*pm, Joe wrote:
On Jun 3, 1:44*pm, CB wrote:

So we're redoing our bathroom and it's out to the studs.
snip
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.

Yes, greenboard is OK. It is a so-so vapor barrier, but its basic
important property is moisture resistance. Best used with setting type
compounds and fiberglass tapes for best water resistance.

Second question - greenboard on the ceiling or no? *Some say it sags.

Definite NO according to one customer service query years ago at a
major drywall maker. Maybe not as important with some of the newer
types of drywall (mold resistant, etc.) now on the market.

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.

Likely your project will turn out quite well. Good luck.

Joe

Foamboard insulates better

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.