When one tiles a shower, ya need either the sloped/pre-sloped pan, the vinyl, tile, sealer, etc. Got a client who want’s a very free-form walk-in shower (we colloquially refer to it as a nautilus shower. They’re a nuisance to tile in the traditional way.
There was an article in FHB a bit ago where a formed concrete tub was waterproofed with a paint.
Now, forming a nautilus shower will be easy with the shotcrete techniques we use. My question is, to waterproof the wall and floor and drain, is the paint mentioned in the article sufficient? Is it code compliant? We could also use swimming-pool plaster on wall and floor. Any experience with installing drains with these materials?
Replies
I can't answer your question directly, but it makes me think of a spray-on epoxy floor I've seen in commercial applications around here as a substitute for ceramic tile. I wonder if something like that could work in a shower.
Al Mollitor, Sharon MA
jim, check this out: http://curve.phpwebhosting.com/~luka/articles/Showerpan/showerpan.html
Remodeling Contractor just outside the Glass City.
Quittin' Time
These are also used with handicap showers. There are only three ways I know of doing it, 2 of which are very challenging.
1. The Best way is to use Kerdi, a Schulter product in which the membrane is thinsetted directly on the setting bed and onto their proprietory drain. You will still need a slope for the shower, so plan on a very thick mud bed at the edge of the room. The slope should probably extend well past the shower "area", perhaps 3-4 feet or more. At a quarter inch per foot, that will really mount up.
2. Traditional preslope and membrane method. Membrane should again extend well past the shower area about 4-6 feet. Floor should be waterproofed with tar paper and roofing cement or other membrane below the mud bed.
3. Trowel on waterproofing, like Laticrete 9235. Laticrete may have some specs on this method, but I wouldn't try it. The problem is integrating the surface membrane with the drain. Unlike the Kerdi drain, the trowel on waterproofing does not attach to the drain, so it will leak around the edges. I saw a demonstration once where the mortar bed was removed around the drain for about an inch or so, and the trowel on was taken down to the drain and painted on down there, but it seemed sorta cheezy to me.
Post some more if you have questions.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
In this case, they don't want tile. They will already have the curved walls in the plan (some are compound curves), and a slab, and want an easy way to waterproof it. Tiling that would be a pain, as would be using membranes, and an unnecessary complication at that. They want the feel of being on the inside of a seashell. The structure won't move. It's 2-5" of sprayed reinforced concrete. Can't the waterproofing be simplified? Why not just plaster with swimming pool plaster? It works for pools. Just haven't tried to get one through plan review yet, and wonder if anyone has. The FHB article tub used a paint. Would that pass? What's the flaw in the plan? Where could the system be compromised?
I have an outside hot tub built like this, and it's survived freeze thaw without any cracks. Why can't this work inside?
Thanks for discussing this with me. It helps to have people to think aloud with.
Cal, I've seen that article before (thanks) and it seems to presume tile. We're trying to avoid a whole layer of materials, create an artistic result AND save a chunk of money at the same time.
If they want the finished product to be concrete, my opinion doesn't change. I'd waterproof it with the three options set forth. Instead of tile over the waterproofed setting bed, I would spec concrete. It still has to be waterproofed right? If not this would be mold magnet.
I can't imagine getting painted concrete or gunnite in a residence through plan check let alone through final inspection. The difference is that a swimming pool is, well, a swimming pool. The walls are a foot or two thick; the liquid is undrinkable chlorine infused water, and the water circulates. Mold can't grow in chorlinated water. It WILL grow in tap water that sits on a concrete floor which is not waterproofed and not pitched.
I would have a licensed architect do plans, construction documents, then send it through plan check and pray. Be prepared for a large round of laughing and the ultimate telephone call from the plan checker to the architect: "Are you on drugs????"
This is not one that I would want to construct unless I had wet inked plans by a licensed archtitect and fully plan checked.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I don't question the need for the slope, nor for waterproofing.
My questions are more an exploration of methods suitable to the way the buildings I design go together. Thinking out loud about ways to improve, ways to simplify. We do waaaay more spray stuff than trowel stuff. Thinset and membranes work better on flat, vertical walls than on compound curve walls that lean in toward you. I'm searching for methods that will work better there than the methods that are suited to conventional construction.
In our buildings, we spray polyurethanes, polyureas, acrylics, etc all the time. Troweling a synthetic stucco onto a dome exterior would suck as a job, so we spray it. In like fashion, I'm wondering if there isn't a product that would adapt to this usage--something to spray as a waterproof coat over finished concrete. Or some additive for the concrete. Or....?
What's used on concrete sinks, for example? Seems like they'd have the same water issues as a shower floor. Yes? No?
Came upon some links for people who say they do concrete shower stalls. I'll call 'em tomorrow and see what they have to say.
Following up, FHB #145 March 2002 has a concrete tub that is coated with an epoxy primer and paint from Kelley Technical Coatings ( http://www.kelleytech.com ). It's a swimming pool coating product. Do you think this is problematic?
Cloud-
The problem with swimming pool plaster is that it's meant to stay wet. When it drys and wets repeatedly, it'll start developing cracks. It's also not too resistant to stains (such as drips of colored shampoo), and not as uniform in color as you may think- kinda splotchy actually, especially if the water has a high alkali content. it'd be a bear to clean too, as the surface isn't as smooth as you may think.
Bob
I see all types of "non-conforming" products used in applications that they were not designed for. As a contractor, I would only do this product if plans were drawn up by the owners licensed architect with wet stamp, run throught plan check, installed and signed off by the field inspector. If it ain't Code, then as long as the owner's design professional specs it, and if it goes past plan check, and if it passes field inspection, I'll install cardboard for a shower membrane.
Your paint on membrane is not an approved shower membrane for any City that I've heard of, I don't know if it is mold resistant, I can't say if it would pass a flood test, there are no techical information about its connection or clamping to the drain that I saw, and have no idea if it will take foot traffic.
I don't get paid enough to take the liability for design and build. Just the build part.
I'm sorry if I repeat myself and didn't answer your question with the answer you wanted, "Gee that looks great, build it." But if you have to ask the question, then you are taking a legal risk that you don't know the answer to, which if I were in your shoes, would not take. Sorry.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Not looking for any specific answers. Not presuming anything. Just exploring solutions for new ways of doing things, be/c sometimes my applications are less suited to the traditional approaches. Sometimes there are workable solutions and sometimes there aren't. Won't know if I don't explore.
I wonder if the author or editor of that article gave any thought to the code compliance of that tub? No mention is made...
Hey Jim, how bout this stuff. http://www.liquidsiding.net/index.html
Supposed to be mold resistant, waterproof, etc... I don't know how it would hold up to traffic, but it is a spray on application that should conform to the curves.Frank
Came upon another possibility that's been used for my application and others. Waiting for the right guy to get back to me with their experience with code compliance, etc. We'll see.
I know we've ben down this road before ...
how was the issue of a leak proof drain assembly addressed?
I know Boris has said Kerdi "could" be used ....
Never used Kerdi ... does it look like you can skim coat the Kerdi with the concrete topcoat and still have a decent looking drain?
Couldn;t wrap my head around that detail last time.
JeffBuck Construction Pittsburgh,PA
Artistry in Carpentry
Kerdi is a very thin, like less than a 16th, sheet membrane that is thinsetted over the setting bed (Hardibacker, Concrete, Durrock, Pick'em).
Its uniqueness is that unlike every other surface applied membrane it mates with a drain assembly to form a waterproof seal.
It does that by a proprietory drain assembly that unlike every other shower drain, has the flange above, not below, of the setting bed. Most shower membranes run below the final setting bed, right?, clamped together by bolts and mud on top, OK? The Kerdi drain has the flange sitting right on top of the setting bed, so the membrane is glued right to it.
You still have to slope the floor, but no membrane sandwitch.
It is not Code in most cities, and is experimental here; it has been used for a decade or so in Europe.
Other surface applied membranes are fine for the floor, but how are they "connected" to the drain? They aren't. If it is a sheet membrane it is simply trimmed close to the drain, and you pray and watch it leak. If it is a trowel on membrane, it is sloppily applied over the drain, and probably leaks, too.
It is great stuff, but tres expensive and not for every application. It is perfect for European type walk in showers where the whole friggin floor is a shower, e.g., a shower and bath without walls.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
so ... could we pour some form of concrete on top of the kerdi?
Up to the edge of the drain lip?
My thinking ... water'd still get under that top layer ... and sit ...
as I'm guessing that drain had no weepholes?
Or am I ... all wet!
Like Cloud said ... there's gotta be a way .... I just can't think of one for the life of me.
JeffBuck Construction Pittsburgh,PA
Artistry in Carpentry
That other app was meant to be tile, and it's still in the works. Wish those clients would ____ or get off the pot. This one is with the expressed desire by the client for no tile. Looking at a product that could be like the membranes, but spray. It's a material I've seen before, and it'd have every bit the toughness of the membrane. Their technical dept is getting me an answer.
I wondered about concrete over the Kerdi, too, but geez, all the overlaps of the Kerdi that we'd have to do to fit a compound curve... Still, I very much like Kerdi and was glad to learn more about it through Boris.
We'll see what they say about this other stuff.
whooops...
look above....
No, you would not want to pour another layer of concrete over Kerdi, it defeats its purpose, which is a surface applied membrane. If you going to pour anything over a membrane, might as well use something cheap and stupid like a PVC shower membrane.
No, the Kerdi drain doesn't have weep holes. It doesn't need any, because it is on the surface.
It probably doesn't work for a room with a concrete finish coat.
As I thought earlier, the only real way to do this with concrete and make it a shower and waterproof is to use, well, you know, a shower membrane under the surface. It clamps to the drain, it has weep holes and is 40 mils thick so it will last forever. Its just you have pitch the d a m n thing which a royal pain in the a s s . If this is slab on grade, you can excavate like crazy and at a quarter inch a foot have plenty of room to get to grade. A double pitch, one at the membrane and one at the finished floor level, would be some work.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I am not sure, but I think that tub was done by a KU architect, but the article.
Ask CAG about him.
What about a crytaline waterproofer?
http://www.toolbase.org/tertiaryT.asp?DocumentID=2073&CategoryID=1402
Cloud, If you're thinking of a concrete soaking tub that was installed in the second floor of a house Dan Rockhill is the guy that designed and built it. He talked about it in class, but I honestly can't remember any mention of a sealer or other coat applied to it.
Yes, that's it. He used an epoxy. Go back to school and ask him if it passed code? Just one semester will do.
I'll wait.
Actually, do you have an email addy on him?
sent it in e-mail, you get it?
Ya mean the one that said he's a ________, oops, that was to be secret. :) Yup, got it. Thanks. I'll let you know if he responds.
Here's the response from the author...
"For the shower we made our own membrane system out of EPDM, nothing special.
I use a double drain, one on the subdeck that's flashed in with the rubber
and than another we set as a screed when I do the shower floor. I think I
would do something similar again. No code issues I can recall.
The tub was a different animal, we coated it with epoxy pool finish when we
were done. This enabled us to palm sand the interior concrete and then coat
it. It works well but I don't care for the finish visually."
That is a little short on details about what type of drain (What the heck is a double drain?) and how the EPDM was conncected to the drain. This is my primary source of concern. I question whether the author even pulled a permit, or even had plans, let alone went through plan check and inspection. But this could be outside cities where Code Enforcement is more or less voluntary.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I think you may be correct on the "outside city limits" I can't recall exactly from class, but I believe that house sits well outside the City of Lawrence limits, which is where the Arch/builder is located, and may be outside the local county (Douglas County), though if it's inside that county, the code officials are fairly stringent on their inspections.
Kansas, huh?
I used to get drunk in Lawrence in a dump called the "Red Dog Inn" but that was when Vern Miller was your Atty General. He didn't like me much. But then he also forced a Branniff airplane down to Topeka for serving liquor by the drink.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
I don't know of any red dog inns around town, and I've been around long enough to hear of most of the watering holes, where was it located if you remember?
Cloud,
I would suggest, as others have, epoxy. It's what's used on ferro-cement boats.
Think of the water pressure on the bottom of a deep bellyed sailboat which may be ten feet or more below the surface.
BTW don't confuse epoxy with the less expensive but hugely inferior polyester resin.
System Three and Gougeon are two brands I have used. Both companies are a pleasure to deal with. (System 3 is a little easier to use, less critical in the ratio of the two component mix.)
Good luck
AlanAlan Jones
one thing he did mention, several times...
if you build a concrete tub.. build it in place.... ;)
he had to lift it up into place, twas not fun from his descriptions.
anyway, I'm not a fan.
Thanks Alan.
Thanks, too, Neil. All our stuff is spray-in-place.
I've also seen showers finished with Increte. Checking into that, too.
One thing that I hope you have considered, is if you coat it to make waterproof, it may get a little on the slick side when wet!! How far away are those grab bars that you anchored into the cement walls? It seems like the only problem is sloping the floor correctly, and finding appropriate way to install the drain. You may consider pond installers, they put a lot of plumbing into some koi ponds. Sounds as though you are having fun with a new challenge
Dan
I just put a layer of fiberglass (actually two) on the bottom a treated plywood box that eventually will be a tile tub. I'm actually going to test it tonight. I did put a layer of epoxy paint on as insuranace (tough as tile paint).
Jason
Seems like the problem with using tile has more to do with the walls of the nautilus shell than with the floor. Is there any way to form and pour the walls so that they sit up on "feet" (i.e. water drains freely underneath it) by six inches or so? Then you could do a regular pitched floor and cover it with tile, leaving you free to come up with something more experimental for the walls, which don't get as much wear and may (?) be less prone to mold. You'd still have to find a way to treat the "feet", perhaps by strategically placing them so that they line up with (and are oriented to) the grid of the floor. And it would take some head scratching to figure out how to form (and reinforce?) the walls as well. But it might have a nice feel to it, not be as claustrophobic. By the way, have you considered using glass block for this project? Too cliche for your clients? Probably a lot simpler though.
Thanks for the ideas. When a client asks for something, I feel obliged to research it. They (more than one) want a freeform sculpted shower, and as Jeff said, it seems like the kind of thing that should be possible. Might not be, but seems like it should. Tile's awkward with some of these surfaces, plus expensive. Same with the membranes. The concrete's already there. With all the chemistry being done and all the coating products out there, seems like something should serve this purpose. Don't wanna let the idea go without a fight.
Oops. Didn't read close enough, and didn't notice that it was the client who nixed the tile. My bad.
Good luck.
Cloud,
From what little I know, I think you can get pretty much any shape with fiberglass - they do some pretty interesting things with kayaks. If done correctly, you should end up with a smooth, lovely surface with any color of your choice. Fiberglass certainly has history in shower usage, and with the cement backing it you will avoid the sponginess that people complain about. Sure it's done with membranes, but it seems like if the concrete has already been poured that you have limited options.
Spray on epoxy ,used to seal concrete floors in chemical plants.
Rino linings , pickup bed liner.
Those are the only simple things I can think of and don't know if the rino lining will stick to concrete.
Both of them come in several colors.
"Rino linings , pickup bed liner."
A local "garage remodeler" (installed the fancy wall storage systems) is advertised a floor coating that sounds like one of the spray on bed linners.
Cloud,
The tub/shower in my master bath is of a poured/cast-in-place concrete construction. It is a tapered cyclinder about 18" high and 5' in diameter at the top. This is capped off with a 80" square "deck. This massive object date from the original construction of the house in 1971. It is sealed with a "gel coat" in faux marble. The cap is a matching cultured marble and above that on three sides we finished it off with standard tile over backer type of an enclosure, with glass doors.
The construction of the tub is very durable. I moved the tub out of the area, reinforced the floor and did some other exterior wall work, then moved it back. Rolled it on a closet rod/dowell. In the center is a reduced thickness 6 inch diameter area with a 3 inch drain hole (the bulk of the tub is 2 inches thick). The drain is a standard, off the shelf pvc/spanner/rubber gasket type.
I do not know exactly how this was constructed. It appears as if the gel coat was brushed on after the base was poured and cured. Very durable and you can make it any color you want. Where to get the material? Talk to your local boat builder/repair shop. Long time ago I worked in a plastics shop making tools and wet lay-up fabrications. Not really that hard to work with.
T