concrete floor in a shower
BryanG said:
... floor... stain it or color the concrete. ... using a latex additive to help with water resistance.
another post, to clarify things.
first, the possible addition of a latex additive, is not going to please anyone here in this site, or at any other web site or discussion forum, where people who build showers discuss topics like "how-to". The fact that your "thinset" (that is what it is called) has latex in it, won't please anyone who knows that shower walls need a waterproofing membrane. Whether or not the thinset is this or that, is not a replacement for the membrane.
Perhaps you are currently under the spell of a charming remodeler who has build a shower without any membrane, and
"hasn't had any problems" so far. I happen to know many people like that, so I can imagine it is a common occurrence everywhere else too. You still do need and ought to plan for a membrane. I have seen showers built with a membrane only applied in the corners and on the bottom half of the walls, and one recent thread here mentioned that happening. It was a complaint thread, and the person posting later reported that the guys building the shower "were going to" run the membrane higher up the walls. Perhaps they always intended to, but just ran out after they did the corners and half the walls. Yeah, sure.
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The floor needs it even more.
If you don't do it, you can end up with locker room smell, stale urine smell, mold smell, etc. And other problems including structural.
I know people who say, "there is NO water going to get past this epoxy grout," and other such things, and they don't put liners (membranes) on a floor sloped to a drain. Their confidence is based on their common sense and experience, but it really isn't a good idea to rely on that alone, for a shower that will see regular usage.
Building a concrete floor in a shower is a rare thing, so it will be hard to get advice from anyone who has done it. With or without a membrane.
David