The drywall installers ran short of cement board, so they used a small piece of mold resistant drywall at the top of the wall where the shower head is located (see upper right of first picture). I brought this to the attention of the contractor, but before they replaced the drywall with cement board, the first two layers of mud and tape were installed (see second picture). Our plan is to tile the walls in the bath tub/shower surround all the way to the ceiling. However, the ceiling will not be tiled.

At this point, is it better to have the drywall replaced with cement board, or just tile over the mold resistant drywall? The contractor has assured me that they can cut out the drywall and slip in a piece of cement board under the vertical corner bead running from ceiling to floor on the right and then install new tape and mud for the horizontal seem between the wall and ceiling.

In case it matters, the drywall installers are using ProForm Lite Blue Joint Compound, a "vinyl base ready mix lightweight joint compound."

Cement Board Bath Tub/Shower Surround

Bath Tub/Shower Surround Mudded and Taped


2 Answers 2


That is not a really wet location I would leave it, I just hope they used a setting type joint compound.

This may be an opinion as others may say omg it must be replaced but in the 50’s and 60’s it was common to tile the entire shower over drywall. If the shower was re sealed it lasted 30-40 years if not only ~20 years or that has been my experience on remodels of this age.

I do not see that upper section as a problem as it is not as likely to have constant spray hitting it.

  • I added the type of joint compound being used to the bottom of my question. Jun 16, 2021 at 11:21
  • I have not used a setting compound that is premixed. Proform light blue appears to have characteristics of setting compound the release of the VOC’s is probably the setting method. It will probably be fine. In the 50’s &60’s standard drywall and mud was used on the houses I remodeled and that was for the entire area (I used to check by putting some in water it always dissolved until the 70’s? hot mud holds up in water) water resistant sheetrock was used in the 70’s and backer board in the 80’s I would not be concerned about this area even if standard Sheetrock was used and you have blue.
    – Ed Beal
    Jun 16, 2021 at 14:01

The places where you really want the cement board are around the tub, in case the silicone caulk dies, that's where you get water infiltration (red arrows). Also the side opposite to the shower, especially the corner (orange arrow).

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The part where they ran out of cement board is going to be fine.

You should check the fixtures (green highlight) don't allow water to get either behind the wall, or behind the tile, because these fixtures are directly under the showerhead.

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