Here is what the manufacturer recommends for installing your shower base
enter image description here

I would like to go further with this and create a notch in the studs so I can push the shower base 1/2" closer to the wall (I need this and I also think that using furring strips as the manufacturer recommends is not the best solution -puts some pressure on the cement board AND ruins the vertical of the wall as the bottom side of the sheet is pushed toward the shower instead of sitting parallel with the wall at the base)

Here is what would like to do. IN this case I might add some BlueSkin between the wood and the shower base

My question is this:, overt time, doesnt the cement board get wet and absorbs water in contact with the shower pan? I know there will be sealant and there will be a slope in the shower pan
enter image description here

Update: I am not familiar with the best type of drywall or sheet that I can put there and I want to know if there is one that is absolutely guaranteed that won't absorb water.
From the comments and the answers I have received so far I take it that there is no such a thing and going with the lesser evil is the only option

Update2: this is related to this Question

  • 1
    Stop calling that drywall. :-).. You want Hardie board or cement board and then RedGard or some other waterproof coating.
    – JACK
    Commented Mar 18, 2021 at 1:30
  • Yes you are correct.I could not remember the correct name
    – MiniMe
    Commented Mar 18, 2021 at 1:44
  • Drywall (greenboard) should not be used in a shower or bathtub enclosure. Cement board is not water resistant, if you use cement board you need to coat it with a waterproof membrane. I prefer to use denseshield as it is easier to work with then cement board and already has a waterproof barrier applied to it. There is no need to reinvent the wheel here, if your shower system is installed properly you won’t have problems with water absorption, thus you will not need to notch the studs.
    – Alaska Man
    Commented Mar 18, 2021 at 2:04
  • Nice thing about concrete board is that it won't burn. Be careful with the foam boards if you have any soldering going on! Agree that it is porous and will wick water. The most basic thing is to put poly up before concrete board as your water proof layer. You could also do epoxy grout with non-porous tiles. I'd go foam board - wedi/keri/etc. Commented Mar 18, 2021 at 3:08
  • Please clarify: How thick is the lip of the base that goes behind the backer? Do you want to push the base into the stud by 1/2in regardless? Will there be gap between back of backer and front of lip? And does the backer then hit the bottom of your pan, as drawn?
    – P2000
    Commented Mar 18, 2021 at 4:00

1 Answer 1


Anything called “water resistant” I’m sure will absorb moisture over time, including cement board.

A quick Google search confirmed this:


  • It has to, the humidity will move toward the dry areas
    – MiniMe
    Commented Mar 18, 2021 at 3:36
  • is there anything water proof ?
    – MiniMe
    Commented Mar 18, 2021 at 12:43
  • @MiniMe ...glass, plastic...
    – Lee Sam
    Commented Mar 18, 2021 at 21:50
  • I mean something for this purpose, to install tiles on it, you know, to build a shower :-)
    – MiniMe
    Commented Mar 18, 2021 at 23:52

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