I am remodeling my bathroom, and intend to replace my bathtub and surround. I have started ripping the 5/8 in. drywall from around the bathtub, and I intend to install a cement board and tile all the way to the ceiling.

However, the cement board, Hardiebacker, is only 0.42 in. thick, so I will have almost a 1/4 in. difference in thickness between the cement board and the drywall adjacent to the tub. What can I do to transition properly between the 0.42 in. Hardiebacker cement wall and the 5/8 drywall so that my tiling will look good and smooth?

I have not done a tub surround before, so I am not really sure what the smartest way to handle this.

2 Answers 2


I would ( and i do ) use denshield instead of cement board. It is much easier to use, you score it and break it just like Sheetrock. It is textured so you want to make sure you set it so it is just inside you tile line. You need to tape and roll on a waterproof membrane over the seams and joints, also membrane on the screw heads.

  • So it doesn't need thinset in the seams? Waterproof membrane, like redguard? Also, have you used this product on bathroom floors, directly on the subfloor?
    – l3win
    Aug 3, 2017 at 18:50

I would shim out the studs behind the Hardiebacker so it's level with the drywall. A couple packs of cedar shims should do it

  • 1
    I agree, but I wouldn't use wedge shims. Run some scrap lumber through a tablesaw to get full-length, parallel shim material in the thickness you need, or rip some 1/4" plywood into strips.
    – isherwood
    Aug 2, 2017 at 19:38
  • Hi. Thanks for taking time to answer my question. I actually found out that there are 5/8 cement boards out there, from Durock. Seems to be the easiest solution for me, since I have to tile the surround and fit it by the 5/8 drywall.
    – l3win
    Aug 2, 2017 at 21:10

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