I’ve recently removed a big section (about 3’x5′) of wall in my bathroom to install new plumbing. I cut the the hole so the edges are flush with the sides of the studs. I just wanted to run my repair plan by you guys to make sure I’m going about it in the right way.
The old walls are some sort of wall board (whatever they were using in the ’40s) with about 1/2″ of course “mud” with an embedded wire mesh. Its topped with about 1/16″ of fine plaster. They are a little over 3/4″ of an inch thick. In the process of cutting the hole and removing the old ceramic tile some of the finish coat of plaster has pulled away from the base coat. I’ve removed all the loose stuff so what remains is sound, but has a sandy surface.
I’m going to sister some 2×4’s onto the old studs so when I put up 1/2″ cement board it’ll be even with the old wall surface. Then tape the seams using fiberglass mesh tape. What I’m unsure about is what kind of material to use where the cement board meets the old walls and have it adhere well to that sandy surface. I was going to use thinset for the cement board to cement board seams. Can I use it for the other seams as well?
Also, should I put a vapor barrier behind the cement board or use some kind of paint on waterproofing? Its an interior wall.
thanks,
bvd
Replies
if your joint is getting tiled over then thinset is better. drywall mud and moisture dont get along.
for behind the backer board, apparently its ok to have no barrier(unless its an exterior wall) but building paper i think is better than poly. it allows air movement so moisture can dry . but IMO the best is use kerdi band over the front of all seams.
http://www.schluter.com/english/products/2002/sectionh/overview-h/section-h.html
Tmaxxx
Urban Workshop Ltd
Vancouver B.C.
cheers. Ill buy.
I'd use either thinset or Durabond for that joint; depends on what I have on hand.
Both will work and hold up to moisture.