# Curbless Shower on Concrete Slab



## RipOut (Mar 31, 2018)

Hi Everyone,

I'm trying to make my life as easy as possible yet end up with a good result. Right now I have a small bathroom area with a tub and a toilet. The tub is 36X60 and 34" from tub to the wall on the other side of the toilet. Everything fits but not spacious by any means. 

Right now the tile in this area is thick. With the mortar bed it is a good 1.25" above the slab. I'm going to be redoing the tile on the floor and I have a vanity area adjoining the bathroom area that will be tiled as well. I can build up the tile another 1/4" to 1/2" and it will not be noticed. 

My question is this. Can I slope down from this tile to the drain and be alright or do I have to do some demo of the slab? Also, I want to minimize the thickness of waterproofing membrane so I was thinking about going with a few coats of RedGard or equivalent. What kind of drain is the best to use in these circumstances? I don't want to do any demo so the drain will be pretty much where the tub drain is now so no linear drains. Since it will be a liquid membrane waterproofing the clamp type flange system is useless. I only need a system where the drain opening is 1/4" or so above the sloped concrete to allow for tile. 

This brings up another point which I would like everyone to ridicule or at least comment on. If I was to use Durock for the walls, why just not use an epoxy thinset with epoxy grout and call waterproofing done? The same could be done for the floor and actually thinsetted and grouted at the same time since it's a concrete slab. I'm not trying to reinvent the wheel but trying to get a grip on ways to make my life easier and not spend so much time waiting around for things to dry and set up. 

Let's face it. We've all demo'd bath/shower stalls that are decades old with almost zero waterproofing. The studs, plates, insulation etc. show absolutely no signs of moisture intrusion. Heck, in the Texas Gulf Coast area we have 100X more moisture coming through an exterior wall than we do from a minimally waterproofed shower enclosure, especially with an on-grade slab and an older home. OK...let the flaming begin.


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## mstrat (Jul 10, 2013)

So many things going on here...a photo would absolutely help...the short answer is this:

1 - you could probably make a Wedi or Schluter tile shower work barrier free...but without a better visual of what's happening here I can't help much more.

2 - Tile & grout can't be your waterproofing layer, it'll fail you so fast you may not be out of the driveway. The Wedi Fundo system is easy to work with and you can just use their sealant over it, it's far easier to work with than cement board. Schluter is great as well, and in my opinion a little better quality at the end of the day.


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## Xtrememtnbiker (Jun 9, 2013)

I'll skip the ridicule as that's not constructive and say that you absolutely need to waterproof your shower. I've torn out far more showers that have water damage than those that do not.

If the shower is waterproof before tile and grout, the studs and sub floor will look the same in 30 years as they do now. That's rarely what we see when pulling old showers and sometimes it's water staining on a ceiling below that clues the HO into the problem.


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## RipOut (Mar 31, 2018)

*This is for a single story slab only*

Thanks for the input so far. I would NEVER even consider doing this on a second floor, this is for a single story slab house in Texas. My point is this. The bathroom area is in a corner of the house with two walls of the shower being exterior house walls. I have more of a vapor/water issue from the outside of the shower than from the inside. This is an older house so the outside is pretty much the inside. There is a brick façade, asphalt paper, studs, fiberglass insulation, and then whatever interior wall finish is installed. This was standard construction back in the 70's. I'm just saying that on single story concrete slab, is it really necessary to make such a huge fuss over waterproofing if you're not using a curb? Epoxy is plastic and as such, it's waterproof. You'll only be able to hold about an inch of water in a curbless shower if the drain stops up. Having a shower be able to hold any more than that, on a single level house, on a slab, seems like a waste of time. Does anyone really believe water is going to get through the bottom of a single level concrete slab that is coated with epoxy thinset and epoxy grout? Of course I'll put several coats of RedGard down just because it's code but is the code overkill?

My main question is what kind of drain assembly is used on concrete slabs with a liquid membrane? Does anybody have a model number and a website?


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## overanalyze (Dec 28, 2010)

Cut it out, dig it out, pour a new sub base lower, install tray or mud base, waterproof. Done...sleep better.


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## overanalyze (Dec 28, 2010)

...


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## Tom M (Jan 3, 2007)

overanalyze said:


> ...


Did you self level the concrete patch before the ditra? Wondering how much a battle the tile was getting flat around the outside of the shower.


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## overanalyze (Dec 28, 2010)

Tom M said:


> Did you self level the concrete patch before the ditra? Wondering how much a battle the tile was getting flat around the outside of the shower.


Yes we did as well as a bunch of grinding. It was a royal pain because the existing slab had a huge hump in it in one corner. As far as if all the work paid off with super flat tile... I will let you know....lol!


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## Tom M (Jan 3, 2007)

Last time I did it I still needed a bigger notched trowel and leveling clips for 12x12. 
I was feeling like mud on everything would have been easier.

Let us know. Good luck


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## overanalyze (Dec 28, 2010)

Started laying the floor. 12x24 honed marble. 1/2” notch on floor and a 1/4" on the back of the tile. They are setting nice. Only a few spots took a little more. The shower will be a marble basket weave pattern. Glass line will bridge the change.


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