This really isn't any different from a shower-over-tub arrangement. All of the plumbing for the tub will be sealed regardless, so that's all good. When we installed our tub (under the shower) we caulked around all the edges of the tub, even the outside edges and along the floor, so that takes care of any water intrusion in the set up you have in mind. You'll have waterproofing under all that tile and sealed seams, so the shower portion should also be waterproof.

We have that layout. The area around the tub is waterproofed in the same way as the area around the shower. I wasn't there for every step, but there's cement board, then the painted on waterproofing membrane, then the tile. Our contractor did install a vent at the end of the tub that just goes into a closet. I guess the idea is that although there shouldn't be any water there, if there was even a drop, you'd want it to be able to "breathe." But I think it was kind of a "belt plus suspenders" thing.

Did the floor under the tub and shower all get sloped to the drain with the first layer of mortar, then make the second layer of mortar flat for the tub, then slope for shower? so the tub is level and the shower sloped?

The tub is level and the shower is sloped toward a linear drain where the shower floor meets the tub. I don't know if the slab under the tub is sloped, but I don't think so. If the tub leaks, we have more serious problems. But in an ordinary bathroom with tub-shower combo, you wouldn't slope the slab under the tub either, because there's nowhere for the water to go. But maybe I'm missing something. We did take a lot of photos during construction, but were not there for every step.

"But in an ordinary bathroom with tub-shower combo, you wouldn't slope the slab under the tub either, because there's nowhere for the water to go."

Not true. When people are sloppy/careless, and let the shower water spray outside of the tub (usually because the shower curtain isn't closed all the way), the water will find its way through the floor outside of the tub. I've watched water come pouring through the ceiling below the tub because someone was careless about the shower curtain. The tub leg (the wall area right next to the tub) is also very prone to rot because of water penetration.

Just like the OP, I've always wondered how waterproofing at the tub/floor joint is addressed in situations like the above photo. I certainly would not want to rely on a bead of caulk in such a case.

It's about more than waterproofing. Waterproofing is the easy part. squeegeeing and wiping the tub everytime you have a shower as well as the shower section is the hard part. That will get very old, very fast.

When I said "no place for the water to go" I meant that I didn't think people put slopes and drains on the floor underneath the tub. I didn't mean you couldn't splash water out of a tub. (After my grandsons bathe, I accuse them of swimming laps. It's the only explanation I can come up with for the puddles I see.)

I'm not sure why you would squeegee and wipe the tub after a shower. I'm pretty sure my tub is waterproof! (And I don't have hard water.) Do people wipe their tubs dry after they take baths because they got wet? Heck, maybe they do!

I don't know about the installation in the photo, but ours has the linear drain at the tub/floor intersection and all that hardware is waterproofed in place. Plus it's on a slab. Maybe it would be a more nerve-wracking installation on a second floor above living space. I do agree I wouldn't want to depend on a bead of caulk for protection in that situation!

Obviously, this setup is not for everyone. There was a rather heated set of comments I read on Houzz on the topic. But as I recall, the vast majority of the people who hated it did not actually have it. Ours is pretty new, so I'm still crossing my fingers that it works for us. It was a way to get a separate tub and no-cub shower in a small footprint.

(PS Something's going on with GW and I am not seeing followups to most posts for the last week, so not ignoring anyone!)

I believe that in that Houzz topic, the floor under the tub was treated as part of the shower and was waterproofed along with the shower in the preslope phase of shower construction. The whole area was waterproofed and passed the 24 to 72 hour flood test Then the tub was added to the extra-large shower space.

I hope I understand the terminology enough that this makes sense.

The floor beneath the tub should be treated the same way as the shower in a sense that it needs to be waterproofed. There are several ways from "hot mopping" to Kerdi sheet membrane from Schluter Systems.

Couldn't there be a curb built under the bathtub, or the bathtub be raised bit so the floor under the tub was not the same level as the shower floor, to further reduce water going in that direction?

This was our solution........We had a hole in our concrete floor for the tub drain, so waterproofing under the tub would not work. We found a drop in tub that we could order a tiling flange for. The tiling flange added to the back three sides for alcove installation and leaving the front to sit on a wall which will be waterproofed. We have the tub installed, but have not started installing the shower part yet. But I believe that any water on the tub walls will be directed back into the tub with the tiling flange, and any water that falls on the wall acting as the tubs apron and on the shower walls will drain to the shower drain. We may have to put a slight angle or curb on the top of the wall under the tub lip, but not a big deal. It was hard to know which tubs have an optional tiling flange,just keep asking salepersons until you find out. I still like the layout even if it is different than most.

We building a custom home right now where we have a shower and tub combination similar to this one posted above. The tub from Duravit and the sales rep actually recommended such a tile flange just for this purpose. We haven't gotten the product yet but should be installing it very soon. I'd just slope the shower floor and install the tile/tub flange..to your drain. How big is your shower?

How would we do it so it is waterproof?

Many ways. Depends on what what proofing materials you like using and what thin-sets or grouts you plan to use with the tile.

It seems like the drain connections for the tub would be a leak prone spot, and the tub edges...do you know how to make it all waterproof?

This is more an issue with a free standing tub but not impossible

Does it take a special type bathtub?

No but some tubs make this job easier.

This bathroom is a wet room. The shower barrier free. The tub is an undermount tub and much of this room I documented online.

Capillary Breaks for Barrier Free Shower Designs · More Info

This is a progress photo showing some of the waterproofing measures I took for this space.

I wrote this story ages ago. It has more insight within the story and the endless comments.

[WHY TO PUT YOUR TUB IN THE SHOWER[(https://www.houzz.com/magazine/why-you-might-want-to-put-your-tub-in-the-shower-stsetivw-vs~3149263)

Tubs in Showers - Vancouver Wet Room Designs · More Info

Now this barrier free shower with a free standing tub was much harder t build because the tub's drain line and tub filler poked holes in the waterproofing system. This makes it harder not impossible.

Our room is 5'x5'6". Here is an in construction photo

It would have been better, I think, if you had used an alcove tub that has the integral tile flange around the top. I think a vulnerable spot is going to be the flat edges of the rim of the tub where they are against the wall. But if this is an acrylic tub I think such a flange could be bonded. I'm not sure because I tend to spec cast iron tubs and such a flange can't be bonded to cast iron/porcelain.

If using an alcove tub, how would you waterproof the area where the apron meets the floor? Aprons tend to be flimsy and will move when pushed, or when the top of the tub is sat on.

There are tubs like the Kohler Highbridge that are made for both a tile-in front and an alcove installation. Your choices are very limited, I know. I 've seen installations where the entire tub was set up on a curb or plinth of 2-3 inches so the floor under the tub was higher than the rest of the shower floor, so the entire pan would have to flood before water reached the interface between the apron and the tile.

I would say that my only concern at the top of the tub are around the outer corners where they get hit with direct shower spray. I doubt the back wall over the tub will even get wet if you are using a conventional showerhead.

I agree with palimpsest that a tub like that would be best. I went to the stores we have here and asked what they had or could order. I have the best they came up with. This is the first i heard of the highbridge, and I am glad you mentioned it for those who will install tub like that in the future. Too bad its too late for me though

Neon you certainly have some challenges there with your install. Will you be adding any kind of tile flange around the three sides?

What about stone or tile over the tub top?

I might suggest bonding your waterproofing to the tub and then doing a picture frame tile edging on the top with mitered corners. Give the tub kind of a undermount install look.

I would be thinking about water migration from the long tub wall to the shower. Some kind of drain mat would work if installed behind the tile I think.

Lots of work. All of it outside any of the company's specifications I think.

Don't like the 2"x4"'s installed like that under the tub. That should be fixed.

Red Shower Lighting · More Info

I used the recessed space under this tub for a lighting feature. See the gap between the tub and the stone? This is the largest challenge for builds like this. getting this detail right.

Coquitlam Chromotherapy Spa · More Info

This is a tub deck. With some tile mitered in the corner. This way the tile is tipped a hair to the tub's inside. The waterproofing bonded to the tub itself and Laticrete SpectraLock Pro epoxy grout used.

Is your electrical switches approved for that location? This worries me. Too close to the shower door and entry. I would think this will Fail inspections if your having them.

Could putting a shower door with hinges on the right side and making it so the door only swings out, not in, solve the issue with the electrical switches? That way there would be no way to reach the switches from inside the shower. The door would block access to the switches.

I would do that Nancy for sure. In the US you might be allowed to ground fault protect that lighting line but here in Canada we need to keep the switches 3' or a meter away from anywhere there is standing water.

I'm just curious how this project turned out for you. I'm in the process of planning such a set up as well. We did see the Kohler Highbridge tub as Palimpsest mentioned. We were going to then do a slightly recessed front deck so that the water proofing material can come all the way up the front surface of the tub. There is a little flange in the front of the tub that curves down over the wall. That was our waterproofing plan anyway.

Has the design worked out for you though? Some people claim it would make for a cold shower since the space is kind of big. My space looks about like yours. Meaning not very big. Which is the space saving reason I've come up with this plan in the first place. Have you noted the shower feeling cold?

Well, it's a bit hard to get one good pic, but we are very happy with it. Our vent fan has a heater in it which makes it warm and cozy, but I don't think it would be required. It may be different if yours is open above the door? Mine is warmer than an open top 36" square shower in a standard 6x8 bathroom without the heater. Having the tub behind the shower took a bit more thinking as far as making sure everything was waterproof, but it has been a blessing with little kids splashing, a jet tub that we can fill more, and perfect to wash the dog and dry him in the shower (doggy shaking water everywhere!) We used an air bubble tub purchased from the big box construction store with an optional tile flange for the alcove sides and tiled under the front lip for the apron. I moved the inprogress pics to my computer, and im using the phone, so if you want to see any of those let me know, but here's the completed tub and shower.

Thanks so much for all the pics. It looks great. I think my plan looks very similar to what you did water proofing wise. Did you run the water proof membrane up the front of the tub wall or did you put the membrane under the shower and tub area. Or both? Mine is going to be more open than yours (more like the picture you put up in your original post) but I do plan on having a heater in my vent as well. Good to know that worked out for you. Small space wise it's a great solution.

Waterproofing was rolled up the front of the tub, nothing underneath it. We have a hole in the floor under the tub for the plumbing, and per my original post, I just did not see a way to waterproof that area. I think the original post was before I found out manufacturers sold add on tile flanges for drop in tubs so they could be converted into alcove installations. Would love it if you posted a pic of yours here when it's completed!

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).

american standard fold over edge tub - Google Search · More Info

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!

If there are concerns over the affordability of an 1K tub for the project, then the entire project will fall into the category of unaffordable. This is the most expensive bath project that you can undertake. Skilled labor costs have done nothing but climb since this post originated. As have product prices.

Also, no one is getting younger. We are all lucky to keep aging. How long do you think it will be that your tub taker can climb over the side and get in and out? 5 years? 7 years? Even with safety bars, the writing is on the wall for that being a relatively short period of time. 30K+ is an awful lot of money to invest in a design for something that is an awkward and temporary solution.

Wow, OK @User. Not sure why you feel the need to take such a patronizing tone. We are working with a general contractor for a full-gut house remodel and are very aware of labor and materials costs, hence why we are keen to save budget where we can (such as by not spending thousands on a guest bathtub). Our ageing parents don't live with us - this is a guest bathroom that we are keeping their needs in mind for for when they visit. It will also be used by all our other guests, including adults and kids of all ages. I understand that the entire wet room area will need to be waterproofed, as any shower would. I don't see how not wanting to blow the budget on a highly expensive tub means that we can't possibly fathom doing a wet room. I am not really asking for the pros and cons of wet rooms - simply asking for suggestions on the best type of bathtub/installation for wet rooms.