I am currently getting a shower redone after the last one had a leak in the base.

The contractor has put up the cement board on the walls, and then mistakenly placed tile on the floor instead of the shower pan. My only concern is having problems down the road due to any quality issues.

Do you see any red flags here?

Sorry the photos aren't great. I'm going to try to get some better ones tomorrow.

cementboard1 cementboard3 cementboard4 floor1 floor2 wall

Edit: Here are some photos prior to the ones above, after plumbing (Day 2). I don't know what steps were in between then and the cement board being installed and the tiles being laid, other than a replacement of the insulation, at our request. This also occurred after a miscommunication, where some cement board was initially installed first and then removed to access the insulation.

plumbing floor

  • Was the cement board installed with alkali resistant fasteners? Is there a waterproof membrane behind the cement board? What was done under the floor tile?
    – popham
    Oct 20, 2023 at 10:06
  • You have a shower pan that fits this exactly? You're going to remove backer board to get it down in there?
    – popham
    Oct 20, 2023 at 10:35
  • 1
    The contractor mistakenly put tile on the floor instead of the shower pan and you're wondering if that's a red flag? Yes, that's a HUGE red flag!!!
    – FreeMan
    Oct 20, 2023 at 11:11
  • Guess I was hoping that was just really bad miscommunication between the guy and his crew, and hopefully not a sign of skill / knowledge deficiency. We already gave a pretty big deposit so I'm not sure what my options are from here. The company is licensed and had so many stellar reviews.
    – halppls
    Oct 20, 2023 at 11:35
  • Does "placed tile on the floor" mean on the subfloor?
    – Huesmann
    Oct 20, 2023 at 12:24

2 Answers 2


It's fortunately not far enough along to see many mistakes yet. I don't know if it's lens distortion in the bottom image or the wall actually curving, but that edge looks curved. Where the sheets come together in that bottom image, though, there's definitely a butt joint that's too tight. There should be at least a 1/8" gap for the joint mortar to fill. The big gaps in the butt joints that you seem to be highlighting elsewhere aren't a problem. A little too wide is stronger than a little too tight. Typically before tiling,

  • the whole thing would have alkali resistant tape bedded in mortar at all of the cement board joints and
  • the whole thing would have a waterproof membrane painted onto the inside surface (it's good practice to buy fiber reinforcement for the waterproof membrane at inside corners, especially the bottom corners, the curb, and up the side corners a couple feet). I suppose you could have a waterproof membrane beneath the cement backer board, but virtually all installers paint the membrane on the inner surface now.

These steps are messy, so a work-wise installer would complete that stuff before installing any tile. It looks like it's already too late to get the bottom joints taped and the floor waterproofed.

For a shower, the most critical details are in the floor, so I suspect that there are already blown details under your tile.

If you don't know much about tiling and whoever put down that tile doesn't either, then your project is going to end in disaster. If you're looking to learn the nuances so that you can coach somebody else through the process, then Sal DiBlasi owns my favorite tiling YouTube channel. If you're looking to hire somebody, then I suggest imposing the TCNA Handbook's quality standards on the job. If you're blissfully ignorant and your contractor candidate doesn't own a copy of the TCNA Handbook, then you shouldn't hire him. Maybe I would make an exception for somebody who does nothing but Schluter installs, where the surface quality of his prior work could indicate sufficient technical knowledge.


What the pics show give grave doubts about the workers qualifications.

Without repeating what popham has pointed out, there are multiple red flags.

There is no one that would place tile directly over a wood floor, or over wood covered with durock without any PVC liner! Was there then a mud bed and pre-slope?

Additionally the shower valve is the type known to have many defects and leaks. Have it tested under pressure for a good 48 hours.

Stellar reviews usually come from people that don't know or pay attention during construction and only comment on how "beautiful" the finished product is.

The Hopefully there are some specifications spelled out that you can demand be met.

If this is paid for by insurance, give them a call and point out that the work is not being done to best practices and common standards.

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