Give me a few weeks and I will post pictures of my new (tiny) master bath that will have a drop in tub and shower combination. My contractor is installing the tub up against the wall on three sides. He will then be putting kerdi panels (used for waterproofing) from the ceiing to the lip of the tub on all three sides and on the section of the pony wall that connects to the lip of the tub on the fourth wall. Note I am saying lip of the tub, not to the "deck". He has explained that all water on the three sides and pony wall that runs down the wall will only have the option of being routed to the tub (unless somehow the acrylic lip on the tub could absorb water, not possible.) If I remember correctly, part of the fourth wall will include the glass shower door which will be fabricated/installed on a seam so that it also touches the tub at the lip and not deck and designed such that water will run back into the tub. The advantages is that basically this is a setup kind of like an undermount where the tub (and most importantly tub lip) are beneath all four sides that are waterproofed because they are designed so there is no path for water to leave the tub. The down side is that the deck for this top mounted tub is pretty much non-existant, maybe 1 inch or so on all sides. That is okay with me since this was the only tub I could find that met my requirements for size and also, and for soaking. It is the Kohler Greek tub and I can't wait til I can have my first soak. So perhaps you could get your contractor to do what mine is doing and add kerdi panels to the walls surrounding your tub - best if it is in an alcove. If not an alcove, then I guess the only way to provide the kerdi waterproofing would be to add walls to make an alcove. Kind of extreme probably. When I talked to my contractor about a top mounted tub and shower combination, he understood exactly the problems and he has done this before. I even found some very old posts by him years ago when he advised people like you not to do this kind of configuration. So I hope my confidence isn't misplaced. Though the new bath will not be anything to show off because it is so tiny, I will post so people may have an idea that seems logical on how to solve this problem if you don't seem to have any other options. Stay tuned.

Hello! I just found this very helpful thread in my search for for ideas/caveats for installing an alcove tub in a wet room/shower enclosure (total enclosure dimensions are 5'6" x 5'0", so the tub could be placed on either wall depending on tub length). This is for a guest bathroom which will be used by guests of all ages, including our ageing parents. My mother in law only takes baths, but father in law only showers and has mobility issues so we want to avoid him having to step into a tub to shower. We want to avoid blowing the budget on the tub itself, so want to avoid cast iron (due to cost and weight), and limited space won't allow for the added width of a tub deck for an undermount/drop-in tub. I did come across the American Standard Studio fold over edge acrylic/fiberglass alcove tub (photo attached), which seems like a decent option to allow us to tile the front apron, but it only comes in 60" x 30" (which is OK, but it would be nice to know if there are any workable 5'6" tubs we could consider). As this thread is 3 years old, I'm wondering what the latest recommendations are for the type of tub to use in a wet room and how to waterproof it. Any ideas appreciated!

1. No problem I can see with this. Caulk the edges. 2 Setting the tub in morter, if slab, no plastic needed. If plywood, you can use a liner on the floor. On top of morter, really no need. 3. I'm a big fan of Fusion Pro. Use a small paint mixer to blend it up and it softens the grout a bit. Lightly dampen the areas you're working on. Only do small areas at a time, don't let it "dwell" on the surface for more than a minute or two, tops. Take a well wrung-out sponge and go over the area in a circular motion, then clean out the sponge and gently wipe diagonally across the tile, flip sponge and continue next wipe. An hour or so later, you "may" need to take a barely damp microfibre cloth and buff the tile....finish with a dry cloth, if needed.

I'm a DIY engineer, not a plumber, here's what I know: You can install air chambers in the lines (hot / cold) before the faucet. If you are going to get this inspected, make sure that the faucet is legal in your city. Some locales specify the brass in the faucet must be low lead brass. I don't know about two handled faucets - here again everything is going towards anti-scald, one handled faucets. Maybe it's OK for tubs only. I would check it out. You could put poly on the studs, and then install 2' cement board. I would use glue for vinyl flooring.