We have a leak in our master bath which is upstairs and wanted to get some help from those in the know. We reached out to a local company here in Austin which was recommended on here. Our masterbath has a shower bench which we think is the culprit in this situation.

They did an acid wash and put new grout in the corners and under the shower bench. Over time the water pressure chipped this away the gaps under the shower bench showed up again. I had them come out again and they used silicone under the bench and regrouted the corners again.

Now i am seeing a small splint in the drywall on the 1st floor right below the shower. Water is still obviously getting its way out of the shower. I had them come out again today and the owner said they should do the same thing and he really discourages using silicone under shower benches.

I asked him why he can't used epoxy grout to prevent water from getting back there to begin with. He said he wants water to get behind a come out the weep holes in the shower.

From my understanding epoxy grout would prevent the water from getting behind to begin with. Why wouldn't they choose that product rather than doing the same thing before which clearly isn't working? TIA.

I was about to say grout doesn't keep water from getting behind the tiles but saw you mentioned epoxy grout which I don't have experience with but it does seem to be more resistant to water pass through than regular grout.

At this point, it seems the best option would be to remove the bottom row of tile, tile just above the bench, and probably the tile shower floor to expose the shower liner. More than likely you have a plastic liner unless someone paid for the upgraded kerdi or other water proofing membranes. This plastic liner probably needs to be replaced to be a permanent solution rather than bandaids. Granted this is the more expensive option but does it pay for itself if the bandaids keep being problematic.

Yep, the water proof barrier behind the tile and grout (if there was one to begin with) has failed. Nothing you see on the surface is meant to prevent water from getting through. People see missing grout and think that's the cause of the leak. It's not. It just makes it faster and easier for water to get through. Filling the gap will slow it down of course, but it does not correct the underlying problem.

Im torn on this. I think the guy who put the grout in really didn't know what they were doing and were using an inferior product which is why it eroded away so quickly. The previous silicone under the bench had worn down and that's how i think water was getting back there to begin with. We went 10 previous years with no issues.

Wouldn't a proper use of epoxy grout and effective silicone be able to remedy this situation? My BIL is an architect in NYC and said they use epoxy grout all the time on big projects including showers at big gyms where they are getting used all the time.

Silicone and the epoxy grout are surface remedies. The epoxy grout would need to be spread out on all tile locations up to the height of the shower head.

The only problem is water can "wick" uphill through all kinds of substrates. If any water finds its way anywhere other than inside the drain, the wicking affect could go all the way back to under your bench which would then leak where it is currently. This is why the only true fix would be to fix the water proofing layer under the tile. This wicking affect would take time but it will find its way to the current leaking location.

even if you manage to seal it up, you might have lots of moisture or mold hiding in there depending on how long it's leaked.

time for a new shower