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Screwed through PVC shower pan liner in bathroom shower, salvageable?

last month

First-timer here: looks like the folks renovating our shower screwed cement board to the wall pretty low to the ground in several places, maybe a couple inches above the mortar bed. They also screwed into the top of the wooden curb (highlighted in red). I'm totally naive here, but from what I've read online, puncturing the liner like this is not as instructed, so I just messaged the general contractor to see if this was expected.

Is there a) a situation where this is normal, b) not acceptable, but salvagble with additional warrproofing, or c) is this totally a lost cause and will inevitably lead to leaks regardless of additional fixes? Hoping it's more b than c: could they redgard/hydroban over everything (would I need to worry about mold sandwich?) if the top layer is indeed still sloped correctly, or could we add a layer of Kerdi membrane to the floor and up the walls a bit? Or is it truly a do-over?


I believe them when they said they pre-sloped the bottom mortar bed, hoping the top is also sloped enough too. Curb is wood. No corner dams that I can see as shown in the Oatey instructional video. Cement board is Permabase. Thanks in advance for any wisdom!





Comments (16)

  • last month

    In addition to posting here, find a redit group to post on too. I find way more expert contractors on there than on here so I usually post on both places when it comes to construction issues and methods. Lots of caring passionate trades people over there.


    I'd figure out the problems and potential solutions before talking to your guy again. You want to be able to list to his solution and then tell him how you want it to be done.

    J Bathroom Reno thanked Kendrah
  • last month

    I talked it over with them and they said the plan wasn't to to do mortar bed + PVC shower pan approach, but rather the PVC was just a backup, the top is concrete and that would be the primary way for water to drain. They were going to use redgard over the floor and walls. Does that make sense? It sounded plausible when they were explaining it.

  • PRO
    last month

    These guys are complete idiots and need to be fired immediately. If you move forward with them, the rot and mold are on you.

    J Bathroom Reno thanked Minardi
  • PRO
    last month
    last modified: last month

    Bullspit. They do not know what they are doing. Probably the 2K low bidders when the job should be 10K.

    J Bathroom Reno thanked Monique
  • PRO
    last month
    last modified: last month

    Terminal ignorance is not curable. I'd bet they don't even own a TCNA Manual. https://tcnatile.com/products/publications/2025-tcna-handbook-for-ceramic-glass-and-stone-tile-installation/ If you haven't posted this in the Tile the World group on FB, do so. They will roast him alive.

    J Bathroom Reno thanked Pegasus Support Services
  • last month

    Can everybody say more about why this contract is a complete idiot, why their way should not be done, and what should be done instead? I like to educate myself when I read these threads and would benefit from hearing more of the 'why' behind these opinions.

    J Bathroom Reno thanked Kendrah
  • last month
    last modified: last month

    Same as Kendrah, would love to know what is technically wrong. I can tell it's not the kind of work you see in YouTube videos, but what technically is causing folks to consider it a catastrophic failure (redgard/hydro ban as a shower pan liner sounds like a legit, if not exceptional, approach)? I'm definitely willing to tell them to rip it out and I'll find a shower specific installer if it's a for sure failure (as opposed to not fine craftsmanship, but mostly good enough).

    As for the curb which I'm worried about, they were planning to take the flap of PVC that's currently on the "curb", and pour concrete(?) on either side of it with the liner in the middle standing vertical. It would be redgarded and then our tile threshold on top. So no screws... The screws into that "curb" were just to temporarily hold it down, and it would be cut away.

  • PRO
    last month

    You never use a liner flat on the floor. Wrong drain. Wrong mud mix. Wrong screw schedule in everything, but especially in the screws too close to the pan and on the curb. You don't put melty mud on top of that and then use a liquid applied membrane. You don't use a liquid applied membrane with any of that. You create mold sandwich. Not sure what is going on with the curb being too close to the pan and not tall enough, but there needs to be a minimum of 2" of height between the two, and that's not 2". And that is the worst sloppy hot mess ever in existence.

    J Bathroom Reno thanked Pegasus Support Services
  • last month

    @J Bathroom Reno - When I had my bathroom done, I had the contractor specify in the contract exactly how it would be build and what materials and brands would be used. Then I posted the language here for review before I signed the contract. Then I took pics along the way and posted here to make sure it was being followed.

    J Bathroom Reno thanked Kendrah
  • PRO
    last month

    If he is trying to do some weird attempt at curbless, more than just the shower will fail and leak.

    J Bathroom Reno thanked Monique
  • last month
    last modified: last month

    I agree with @millworkman:

    -The walls should not be embedded in the mud. They are already showing signs of wicking water up. That will be a big problem when the floor gets wet. This is a redo.

    -The screws puncturing the membrane are a redo. No fixing that.

    -They don't know what they are doing on the base. There's a pre-slope, a membrane, and a top mud coat. You don't mix and match by painting redguard on it. The top coat looks bad. I've never heard of building a curb like that.


    All-in-all, I have to conclude this person doesn't know what they are doing. Hot tip: Stop now. Don't let it go forward at all. This will be a mess.

    J Bathroom Reno thanked Jake The Wonderdog
  • last month

    Thanks all for the advice on what's going on, I definitely felt more confident after hearing from everyone here. Talked it through with the general contractor and agreed to discuss options tomorrow, including ripping it out and starting over. I'll look into alternative installers as well.

  • last month
    last modified: last month

    Post this over on John Bridge Tile forum. The pros over there will provide you with everything that's wrong with your shower/pan/curb. They were VERY helpful to me a few years ago.

    It was funny because they not only gave me a list of everything that was wrong - they also listed "explanations" my contractor would use in order to "justify" that it had been done correctly. So, I knew what he would say and how to respond.

    It needs to be ripped out.

    J Bathroom Reno thanked dani_m08
  • last month

    " walked it through with the general contractor and agreed to discuss options tomorrow, including ripping it out and starting over. "


    There are no options here, it all comes out and a different sub is put on the project. The curb should not be wood either, even with a pvc liner.

  • PRO
    29 days ago

    O M G! Nothing there should be moved forward with. Where did you find this ”GC”? Are you 100% sure that he is licensed and insured?