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Help! Contractor did not put waterproofing under shower floor

J Indiana
last year

My husband and I are homeowners: we just finished building a slab on grade house. Our finished floors are the concrete slab itself, including in our walk-in (no threshold) shower. The floors were simply buffed smooth when they were poured, and we sealed all of the concrete with a water-based acrylic sealer, including in the shower. Pic:



The first time I took a shower, I noticed that the water was soaking into the concrete around the drain (as if the sealer didn't take there), and I realized that there was probably nothing stopping water from soaking into weaknesses in the concrete sealer and going through the slab, possibly to other parts of the house. (I have not taken another shower since.)


I did a quick Google search and saw that most people said no-threshold showers need waterproofing under them that connects to the waterproofing on the walls (but most of the posts were about tiled floors, not concrete). I decided to confirm with my contractor that we had this, because I didn't remember anything sticking up from the slab after it was poured. I assumed he would say we had it, but instead he said there is no membrane beneath the shower floor because that would have required two pours (the house's whole footprint was done in one), but there is waterproofing on the walls (I don't know what it's called; it's purple; pic attached) and the shower-adjacent walls were framed with wolmanized wood, so it should be fine. (The walls are covered in tile.)




This didn't sit right with me, so I pulled up the Indiana (were we live) plumbing code, which did not specifically say anything about no-threshold showers or floors that are concrete slabs, but it does say there needs to be waterproof liners under "shower floors" and that they need to tie into the drain and connect to the waterproofing in the walls by at least 2 inches. It doesn't seem ambiguous to me.


The contractor said the he had "professional concerns" at the time, but he is insistent that everything is fine, although he has not been able to explicitly tell me how we meet the waterproofing requirements of the code. He and the architect say that what little water penetrates the sealer will just evaporate up through the slab again (there is plastic sheeting under the entire slab, plus a bunch of rigid insulation that has been sealed with tape, because this is a super insulated, airtight, energy-efficient house).


He said the drain works like any other floor drain in concrete, like we have in our utility room and like other houses have in their basements. He does not think (as I do) that water can seep into the slab at weak points (weaknesses in the sealer and particularly where the floor meets the walls) and migrate to other areas, specifically the wood and drywall on the other side of the shower wall (where our laundry closet is).


For the record, he did not voice his "professional concerns" to us at any point, and he did not once explain to us how a no-threshold shower poses more challenges than a traditional shower. We had no idea (busy worrying about other things). Even if this isn't a code thing and the waterproofing relies solely on us reapplying the sealer vigilantly, we would have been like "forget it; it's not worth it." But none of that was explained.


The other problem is we built in a city where the inspectors don't really inspect anything. The house passed inspection (there was no watertight testing done to the bathroom, that I'm aware of), and we already closed on the house. So I have a few questions:


1. Is it in anyway possible that this shower is fine and meets code? The baffling thing is that no one on the team -- the architect, contractor, project manager, plumber, or tiler -- ever made a peep to us about this shower idea. They never explained the challenges of creating it or any risks associated with it, so we had no idea that there were any and had no reason to believe they weren't doing something correctly. We have generally had very good collaboration, have found the contractor to be very honest, and I never got the sense that anyone wasn't putting in their best effort or that they were trying to cut corners. We've had to bend on other things that didn't match practical reality, so we would have understood if we got a "we can't do that" about the shower floor. The contractor has not made any qualms about coming back to the house to fix smaller stuff. So this is truly puzzling. Is there any waterproof-liner exception that anyone knows about for shower floors that are the slab itself? Or is the contractor absolutely wrong here?


2. If it's not to code, does the contractor have a legal obligation to fix it? He is telling us that a built-up shower can be installed, but it sounds like he is only willing to do a small portion of the prep (take a few rows of tiles off the wall), and not build the shower floor itself (we'd have to find someone else to do it). Part of me is ready to be done with it, but (1) this seems like he is escaping is liability for future damage. If someone else works on it and there is water damage, then he can blame them and no longer has accountability and (2) it seems like there is going to be extra expense associated with building up the shower, which wouldn't have happened if it was done right to begin with. It doesn't seem right that we have to pay for his mistakes + a new shower floor.


Sorry this post is long, but I wanted to explain it all. I've been working with this guy for over a year and it does not seem in his character to (1) do something so wrong and (2) not own up to it. I wanted to crowdsource some thoughts before I push back too hard (I like our relationship and don't want to damage it), and honestly, I'm hoping I'm the one in the wrong here.


All thoughts welcome! Thank you.

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