We had a new shower put in (by a contractor who was in over his head) during a remodel a few years ago. About a year ago the built-in-bench starting to collapse. When we pulled out the bench we noticed that there was no shower pan under it- eek! We need to add one.

Here's my question? Can we simply fill it in instead of starting over. Every contractor that has looked at it says that they have to pull out the existing floor (which includes the tile that I'll have a hard time replacing). I don't mind having to replace wall tile... i just want to avoid pulling out the floor.

I'm convinced that there has to be a way even if it's unconventional.

current shower situation

  • What's the liner material we're seeing?
    – bcworkz
    Dec 28, 2013 at 22:07
  • Do the contractors that you bring out say why you need to rip up the floor? Could it be something unrelated to replacing the bench?
    – Edwin
    Dec 29, 2013 at 7:31
  • You have options. You can cement another membrane over the existing CPE membrane. You could use a liquid waterproofing membrane like RedGard. It depends on how much of your existing membrane is sticking out and what condition it is.
    – Edwin
    Dec 29, 2013 at 7:36
  • 1
    If the contractor screwed up one part of the shower, other parts are suspect too. Did he cover the weepholes in the drain assembly, did he cut or improperly fold the corners of the membrane, did you fir the concrete board off the walls so any penetrating liquid will drain off inside the membrane. If you have doubt, I'd start over. Better now that in 5 years after you find out you rotted out a joist or two below the shower. Mar 5, 2014 at 7:27
  • 1
    Those benches always leak. If you watch Holmes on Homes or any of those repair shows on HGTV or DIY, they are never made correctly and end up leaking. Usually whoever made the bench incorrectly, also did the rest of it incorrectly as well. You can certainly try to cement on another membrane and it may last you a couple of years, but it's going to have to be gutted eventually.
    – Zach
    Oct 1, 2014 at 15:50

3 Answers 3


Since I can see holes in the pan that look like they were used for installation purposes - nail holes. - An absolute certainty of failure - Tear the whole shower out. Save yourself money in the long run. I have replaced showers that are only 4 or 5 years old with small penetrations in the pan which caused major water damage to structural members. If those wholes had been covered by a sealant compatible with the pan - that would be different.

There is no way you will achieve a water tite system with the wall opened up. - Remember - thinset and grout are porous materials. It is not the tile that makes a shower or tub water proof. If a surface membrane had been used you might have been able to break off a couple rows of tiles and bonded another surface membrane like Kerdi and worked your way down - doing the same to the floor. But that still is a chancy bit of work. Bite the bullet and start from scratch.


As much as we'd rather avoid it, it is still better to pull it out and redo it right. I cannot see what the flooring material is underneath, but it looks like wood, which isn't a good option without a concrete backing board laid on top to reduce flexing. Those walls should also have concrete backing board for better waterproofing and reduced moisture and condensation buildup in the walls.


You do not need a shower pan but you DO need slope to the drain. This can be achieved by either a shower pan or a built-up base. Shower pans are usually in specific sizes and it looks like you have a custom size shower so in your case a built up base is probably your only option.

You can build up a base over your existing floor as adhesion to the floor is not an issue. But a custom builtup base must be properly installed with water proof membrane, usually epdm, and transitioned properly at both the walls and the drain.

You will still need to get under the wall finish so any water coming down the walls gets shed onto the floor and properly get the floor drain installed which will probably require removing the existing drain and reinstalling a new one properly.

  • wall and floor need to be integrated - that is why they are built together. Either for a traditional mud bed or surface membrane shower. Aug 21, 2015 at 7:07

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