Let me start by saying that cement board is the biggest piece of .... invented by the construction industry. I do not know when this cracked but it developed by repeated manipulations of the biggest board

Should I replace the board in the picture or screw it in place as is? enter image description here

I ended up installing a piece of 2x4 in vertical position to add some support where the crack is.I will put two screws above and below the crack Here is the board installed but not screwed yet enter image description here


2 Answers 2


I would add a piece of framing behind where it is cracked. I would also make sure that the waterproofing - whatever you are doing, is done very well in that area.

Other than that you should be fine.

I want to make a few comments here:

  1. Hardiebacker is better than the other types of cement board in general for a tub/shower wall. It is more rigid. The flex from some of the other brands is actually perfect for floors but not walls.

  2. You should predrill your holes for cement board. Actually a double predrill. You just need a very small bit for the screws and a larger bit to pop 1/8" down to sit the heads. Without predrilling the screws often catch and create space behind the board... which causes cracking.

  3. Why is there a huge gap in your corner? This does not look right at all. If you need to move that piece over, yes I would just replace it.

Perhaps you takes some other pictures and we can help more. Dealing with concrete board is not hard once you get the steps right. If you don't predrill, use wrong screws, have wrong type of drill, framing not flat... it can be frustrating.

  • See the second picture to see what it looks like when the board is installed The gap you see there will be behind the board -see this thread diy.stackexchange.com/questions/235025/…
    – MiniMe
    Commented Sep 20, 2021 at 19:28
  • Yes I already went through the framing not straight phase ...that had nothing to do with the cement board though -it was there because of whoever built that wall. I need a glass panel on that wall so it had to be plumb -damn -lots of work to sister everything (I also needed to float the wall a quarter of an inch due to a a shower drain error (it was off that much)
    – MiniMe
    Commented Sep 20, 2021 at 19:30
  • @MiniMe - durock has issues with cracking near edges. You could have circumvented this by the double predrilling. Also double predrilling is actually FASTER than just screwing them in and I have competed against my guys at sites. I drill three holes, screw 3 screws in and board is hung. Then I go through and put in about 20 screws per sheet - hitting everything all the way through with a small bit and popping the top for the heads with a wide bit. Doing it all like that makes each screw take 5 seconds... compared to guys messing with screws pushing board out and cracks...
    – DMoore
    Commented Sep 20, 2021 at 19:39
  • and remember no one is an expert, until they mess up enough times to become an expert
    – DMoore
    Commented Sep 20, 2021 at 19:40

Should I replace the board in the picture or screw it in place as is?

Assuming that you have properly supported the cement board from behind with studs, and you attach it, this should not present any problems.

So as long as the surface is relatively flat and is secure (i.e. doesn't move) it will be fine.

  • There is no horizontal support in that area neither above nor below. The most to the left stud is 1' away and the crack is 8" long. I am not sure if it is safe. It will support 24x24in tiles
    – MiniMe
    Commented Sep 20, 2021 at 16:53

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