I recently tore out my old tile shower walls, and am replacing with go board and new tile. the wide wall (60") is slightly off level from th back of the tub toward the drain. Should I hang the hardboard to follow that path all the way up to the ceiling, or, have an uneven gap between the hard and tub lip?

  • 1
    Please post a photo. It is always better to install everything square, instead of misaligning one thing for another. Commented May 7 at 13:58
  • Tubs need to drain. Some are designed to drain the bottom with the back wall level, others have the bottom level with the back wall, so the back wall has to be tilted.
    – Ecnerwal
    Commented May 7 at 14:40

1 Answer 1


Well, neither. Set the backerboard from the ceiling down, and cut the bottom edge to fit the tub. This is how most wall sheathing is done in retrofit scenarios, including drywall. It can generally be assumed that the ceiling line is fairly straight and level, so it's a good reference.

If doing this would leave you with a very thin strip at the bottom, cut some reasonable amount off the top of the top sheet, parallel with the edge, so that the lower sheet is large enough to be robust. As with anything, a little planning saves hassle later. Lay it out with a pencil on the studs so you know what's coming.

If your ceiling is also out of level, cut the top of the upper sheet to fit that so that the sheet remains level. All horizontal joints should be level when you're done.

Note that some small amount of imperfection is just fine with a substrate like this. If you can slap it all up parallel with the tub or ceiling and have gaps no larger than say 1/4" at any edge, carry on. No need to get fussy with it. You can prefill with mortar and your tile will span that without issue.

  • Thanks much - helpful stuff!
    – LDee
    Commented May 7 at 14:56
  • You're welcome. Please take the tour. "Thanks" comments are discouraged.
    – isherwood
    Commented May 7 at 15:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.