We hired a contractor some time ago to remodel our bathroom. We started noticing things that didn't stand up to use soon after the project was completed. Most of them were minor, so no headaches there. However, one thing keeps happening that driving me crazy.

There's a large gap in the corner of the shower that was filled in with joint compound (I think). The caulk that was applied over it started to bubble up and become discolored. After we re-caulked a few times, it kept happening.

It's driving us up the wall, and I can't figure out if there is a DIY solution that doesn't involve taking tiles off.

If anyone has any interesting suggestions or ideas, I'm basically open to anything.

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  • 2
    That last pic shows that there's bare plaster & lath behind the tile. This will suck up all sorts of water from the shower each and every time you use it!. I don't think there's any kind of product you could put in there now that will properly rescue this. The entire shower surround should have been covered in cement board or other waterproof sheet material with the joints properly sealed, then the tile applied over that. Sadly, it seems your contractor did a really shoddy job.
    – FreeMan
    Oct 23, 2020 at 11:19
  • 1
    Agree 100% with @FreeMan here. This is shoddy work and water is now damaging everything behind and under your shower walls and floor. Do yourself a favor and get this all torn out now, all the rotting wood replaced, and a shower installed properly. No amount of patching or caulking will make this right.
    – jwh20
    Oct 23, 2020 at 11:50
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    Your best remedy, and I hate to say this, may be to find out if/where your local building code requires waterproofing a shower/tub surround (I'm certain it does) then find a sleazy lawyer to threaten/sue the contractor to come back and redo the whole thing on their dime. Better yet, to have the original contractor pay a different contractor to do it properly (since they don't seem to be able to be counted on to do it right the first time). Ugh... That was nasty to type. I feel like I need a shower now!
    – FreeMan
    Oct 23, 2020 at 11:57
  • @FreeMan Sometimes it's better to just cut your losses and move on. While a small-claims case might be suitable here, I would not ever trust someone who did this kind of work to do anything else.
    – jwh20
    Oct 23, 2020 at 12:36
  • @jwh20 hence the suggestion to have the original pay someone else to do it. Yeah, I didn't really like saying that. Shudder... Depending on how much $ was spent on it, it's a possibility and helps get across the seriousness of how badly this was done.
    – FreeMan
    Oct 23, 2020 at 12:47

2 Answers 2


IF this is your only issue with this shower then you will have to borrow from the cheap hotel maintenance mandate of fixing shower corners.

That would be placing a strip of plastic (pvc) or glass along that whole corner.

This is how it works.

  • you get a 3" by "1/4" piece of glass or pvc that runs up the entire corner (high enough where water shouldn't be entering the top)
  • epoxy/glue that to the back wall
  • caulk each side and the top

The only weak point after doing this will be the very very bottom. You just have to recaulk that frequently - every 6 months or so.

In my teen years I did this for a hotel chain using very flimsy shower pvc. It would generally give the showers another 1-2 years which in the hotel world is like gold.


I agree that this is indicative of not having proper water proofing behind the rest of the tile and that significant damage (rot,mold,mildew) could occur to the wood behind the tile if left for years.

If tearing out the whole tile wall and doing it right is not in the near future and you want a stop gap measure ;) then you could water proof it the best you can.

Mask/tape ALL around the opening and then "paint" the whole inside of the gap with an elastomeric waterproofing membrane such a RedGaurd. Use a disposable paint brush and give it 3 or 4 good coats of the membrane in the back and on the sides.

Once it is dry you can Caulk the remainder of the gap with mold and mildew resistant 100% silicone caulk. If the gap is deep you can fill the void with backer rod so you do not have to use successive layer after layer of caulk to fill it in.

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