Home>Discussions>BATHROOMS>Vapor Barriers in Bathrooms?
2 posts / 0 new
Last post
Pamela Cooke
Vapor Barriers in Bathrooms?

I'd really appreciate any guidance on the murky question of vapor barriers for bathroom walls? I'm under pressure hanging the last sheets of drywall and the taper comes tomorrow.

Our first floor shower tub has living space above it. There is no window in the bathroom, but a powerful exhaust fan. We have low outdoor humidity and have more days needing heat than cooling.

The tub/shower is against a 2x6 drywalled garage shear wall and against the 2x6 sheared wall of a tall underhouse space wall. I insulated those 2x6 walls with kraft-faced insulation, kraft side towards the tub. I have tyvek over the inner side of the studs hanging just over the flange of the tub where it starts to go flat. Then hardiebacker for tile (not done yet). The shower ceiling is lowered, leaving a 24 " high empty space above it with no insulation directly above the shower ceiling. The insulation above is in the joists 2 ft above the shower ceiling, kraft face facing upward to that warmer space. Does this empty space give room for the steam to evaporate? Should I change things to avoid problems? It will be difficult since the drywall is hung, but at least it's not taped yet.

Thank you so much!

Timothy Miller
Re: Vapor Barriers in Bathrooms?

What direction is the garage wall hopefully not the north side of home. I would add plastic before the hardie board and sheet rock as it is cheap and stops the moisture. Heck a couple tubes of caulk run on the studs to seat the nail penetrations is good too. The type of paint on the ceiling will also influence how much moisture gets above it.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.