I had to shim the studs for the cement board (to install the cement board over the tub lip). Now I am left with a gap between the cement board and the drywall.

On the right hand wall, The gap from the face of the cement board to the drywall is about 3/4”.

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The gap on the LH side of the wall is about 1/2”.

enter image description here I’d like to avoid adding another layer of drywall to make the surfaces flush with each other to make the transition. Any other ideas on how to complete this transition?

  • What do you want for the final look? There are lots of ways to do none matching surfaces. A hard sharp corner, a sloping trim/transom, build up/add more drywall for a smooth wall, hide it with a wall/door/shelving.
    – crip659
    Jan 5 at 22:30
  • I am not very picky, just want to close up the gaps and make a transition. I went to the tile store and picked up some pencil tiles, bullnose, and a few random trim pieces but none of them look good on both sides of the wall due to the different gaps.
    – Niko
    Jan 5 at 23:43
  • You need some kind of molding to cover the gap and then you can tile up to it or over it. Vinyl molding would be good option due to the probability of high moisture
    – DJ.
    Jan 6 at 0:20
  • Building out the wall so that the cement board can go over the top of the tub flange is consistent with all of the details in the TCNA Handbook. I'm a by-the-book person, but the book is wrong on this one. The tub flange should be tight to the wall studs, and then the cement board should stop at the top of the flange. This will leave a 1/2" tall air gap along the tub flange behind the tiles. Cantilever the bottom row of tile over this gap without filling it.
    – popham
    Jan 6 at 7:52

1 Answer 1


Plastic molding strip from floor to ceiling. Butt the tile to molding, no fancy edges needed. Paint the molding to match wall. Caulk all joints. Will last for decades.

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