Mysterious shower leak

[Jeff H Young]

flat surfaces without water proofing or water proof with holes in it I dont see much never saw cement board on a seat. of cource once I pass my inspection what the tile guy does I dont much see because I really have no reason to be on the site and theres a short amount of time. and I see over 90 percent hot mop and mud walls , floors and seat that I cant guess how they would do it. After some thought I think I agree with jadnashua there is a lot of improper work that goes undetected

 

[WorthFlorida]

Your photo shows a PVC liner that goes up over the bench (does the base have the proper preslope over it?). So putting concrete board over that is not the best practice, the screws will puncture the PVC liner and render it useless. I think it would be OK to just omit the PVC liner on the bench (which should be sloped to drain rather than hold standing water) and rely on the concrete board and RedGuard. Or if you prefer the liner on the horizontal bench, then the bench and wall below it should get a mud job, just like a giant curb (assuming that would work).

Cheers, Wayne

I wasn't there when the seat was tiled. Thinking about it the seat probably was not covered with a board. Makes sense about holes. You can see the liner on the floor goes up about 4-5" and that was also up the seat wall under the seat cover. This was completed around Dec 2017, and no issues at all. There were two tilers, the first pair of guys did most of the floor but they seems to quite the job so a another guy, may be 60 years old or older, worked alone and was slow, but he was a perfectionist. He used sewing thread to make his lines to be perfectly straight. He also removed some of the floor tiles from the first tiler to get it right to the shower base. It's one advantage to use a bath remodel company where a tradesperson decides not to show up anymore. Of course they were all subs.

 

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[Jadnashua]

There are ways to not require a waterproofed seat in a shower...one method is called a monument bench. You waterproof the shower and then make the entire seat out of water tolerant materials...like a big stone monument. That it might get wet is irrelevant.

By far, though, the 'cleaner' way to make a shower waterproof (note, code only requires the pan to be waterproof, but everything else must be water resistant) is with a sheet waterproof membrane. That way, all surfaces can become waterproof up to at least the height of the showerhead (and you could go all the way onto the ceiling, if you wished, and would be required in a steam shower).

Depending on the dimensions, and location, Innovis makes a series of products called Better Bench, that are 'hung' on the walls, and anchored into the wall. I put a corner one into a shower I did for my mother. They also have some small corner units just so you could say put your foot on it to shave.

Schluter has benches that are formed out of structural foam, that then get covered with waterproofing sheeting, or, you can make them out of their KerdiBoard sheets. Wedi makes some similar sheets, and can provide a totally waterproofed shower as well. People get queasy about foam, but keep in mind, they have been using it on the approach ramps to highway bridges and overpasses for awhile now...installed properly, it can easily handle the weight, are inert, and waterproof in their own right. They also have some corner shelves you could put in as a foot rest, or to hold various things. Noble was the first sheet membrane certified by the plumbing codes as viable for showers...Schluter came shortly afterwards, and both of those have been around since the 1980's, so neither one is 'new'. Some people still haven't heard about them, but both are multimillion dollar companies and Schluter is a multinational one with two major facilities in the US.

As I said before, there's more than one way to build a reliable shower, but it's detail oriented...you must cross all of your T's and dot all of your I's if you want it to perform and last. Personally, if it weren't for cheap labor, mostly in CA, hot mopped shower pans would no longer be used...it's not particularly green, has a lot of VOCs during install, and is just as prone to failure as other methods. Getting a proper, consistent slope can be an issue, too.

FWIW, there's no good way to put cement board on a curb or a bench when using a liner, and it's not generally accepted to do that with a liquid applied waterproofing unless you are REALLY careful. That makes preparing the surface of a bench tougher to get a thinset compatible layer while maintaining water integrity tougher and is where sheet membranes start to shine.

Take a few minutes and work through this for an idea of one way to do things Waterproofing Tiled Showers (scorm.com) There are other products and methods that can work well, too.

 

[Themp]

I would attempt to fix this myself with a bench top of man made Quartz. I know it is kind of a hack, but at this point you have demoed the top of the bench and now can install the support and corner structure for the piece of Quartz. Make sure the top is sloped and has a good over hang, instead of being square. I see no water damage on the tile you took out on the walls. I assume no damage can be seen on the tile front of the bench. I would water proof the heck out of the inside. All new grout for the tile should be sealed or use epoxy grout.

https://lovecreatecelebrate.com/what-material-should-you-use-for-a-shower-bench/

The foam board being used in this seat for support looks interesting.