DIYbanter - View Single Post - Advice on Sealing the Joint Between Drywall and Cement Board?

wrote:
In the process of re-tiling my walk-in shower, I removed the old
drywall about 6 feet up the wall (that's as far up as the old tile
extended) and replaced it with DuRock cement board. I've got the tile
all set, except for the top 2 or 3 rows. I'm wondering how to seal
that 1/8" gap between the top of the new DuRock and the bottom of the
old drywall. There's not only a gap between them, but they are also
slightly different thicknesses. So, if I wanted to use slightly taller
bullnose tiles for the very top row, which would extend them past that
joint, the tiles wouldn't set flush because of the differences in
thicknesses of the drywall & DuRock. Should I put an extra thick layer
of Mastic in and around the joint and feather it out like you do with
drywall joint compound, let it dry and try to sand it to smooth it out?
Or maybe just use drywall compound itself and Mastic over it once it's
dried and sanded?

So you'll have tiles only up to six feet? I would go all the way up to (
and tile also) the ceiling. Wondering how high is your shower head. The
pipe on mine comes out of the wall at 6' 6" and nobody in the family is
very tall.

Anyway, don't you think that moisture will get to the area left with
Sheetrock and without tiles?

The different thickness between sheet rock and durock and that 1/8" gap
are the consequence of poor design in my view. No offense meant, but I
would reconsider those choices.