curbless shower. how, if possible?

[cookevillain]

Hi everybody!

My name is Alex and I am an amateur. My question regards building a custom shower floor. I have a friend who is in a wheelchair and I would like to build a bathroom which he can use while visiting me. The main problem is how to build a shower which he can just `wheel in', i.e without a barrier. I have seen it in a few design books but never any technical details. I have ordered John Bridge's and Michael Byrne's books and also the TCA handbook, hopefully they will have some details. Here are some specific questions:

1. the recommended detail for the floor calls for about 2.5" of thickness 2' away from the drain (1.25 layer of concrete, 1/4" per foot pitch, 1/2" tile thickness, 1/8" allowance for CPE, etc. ) not counting the subfloor. My existing floor is 2" thick WITH the subfloor (I have 1x10 boards covered by 3/4" plywood as the subfloor and 1/2" thick carpet). To match the thickness of the existing floor, what do I do? One idea I considered is to install a 4'x4' sheet of 3/16" steel directly on the joists and building a shower floor on top of that. This still leaves me with a 3/4" extra thickness but I can manage that. I would really like to avoid notching the floor joists (it is prohibited by the code, and sounds like a bad idea structurally, anyway)

2. now for the curb. I was thinking about just leaving a 1/4" per foot 4'x4' `indentation' in the floor with the drain in the center for the shower and a flat floor surronding it but I am wondering if it will lead to moisture penetrating under the tile and destroying my floor. I guess I can just cover the whole bathroom floor with CPE. Is this acceptable (cost considerations notwithstanding)? Are there better solutions? Do I have to do something special to get the CPE sheet adhere to the subfloor in this case? Finally, in this scheme, do I still have to place a 1.25" thick concrete layer on top of CPE (if for nothing else than to hold the CPE sheet in place)?

Thanks in advance for any suggestions. Any reference to materials on the web is appreciated.

Alex

[bbcamp]

Hey, Alex in Cookeville!

You'll want to use another type of membrane for this kind of shower. Kerdi will work well for this application. Do a search on curbless showers and Kerdi (together), and you'll see several threads dealing with this.

[dgunnels]

Bob, if this is a new build could he just do a concrete/mud floor. Kind of an industrial thing? I've seen that in some mags and liked the look.

[cookevillain]

Bob,

Thanks for your quick reply. I have looked up the Kerdi system and will probably get John Bridge's book on the subject. I will post new questions after I have done enough research.

In the meanwhile, my structural engineer wife told me that there are several ways of reducing the height of a floor joist (she said the code allows sistering a 2x10" to strengthen the beam). Since she is an engineer all she is thinking about is loads and sure, the joist will be strong enough. My question is, if I notch out an inch over 4' will it negatively affect the joist's characteristics as far as tile goes? After all, I will be standing (and showering) where the joist is thinned out. The joists span 11', 16" on center. The area I plan to thin out is about 3' from the end and is going to be 4'-5' long.

Neesie,

It is not a new build, I am remodelling my bathroom. Did you mean just having a concrete floor (sealed) without any tile? I looooove concrete (I would make my coffee mugs out of it ... if it held water) but how feasible is it to have a concrete floor in the bathroom? Even the best nonporous HSC 40,000 psi mix (with silica fume) absorbs water like crazy. Can you seal against that?

Thanks again for the advice.

Alex

[jadnashua]

No, you really don't want a concrete floor shower...

[John Bridge]

Hi Alex,

I won't go head-to head with a structual engineer, especially a wife/engineer.

Cutting down the joist height in a shower area is usually feasible, though. You might have to add sisters depending on where the supports are located now.

Get The Kerdi Shower Book. You'll need it.

[e3]

Nobleseal is made from CPE. WE CAN DO WHEELCHAIR SHOWERS!!We have details on line also.

[bbcamp]

Notching near the ends of the joist have less effect on deflection than notching in the mid span area. Sistering the joists makes up for the lost material. You needn't worry about that, especially if a strtuctural engineer/spousal unit gives it the Oaky-Doaky.

[cookevillain]

John,

Thanks for the advice and the book (got it yesterday, printed it out, it is completely covered in yellow highlighter already ). I would not want to go head to head with my wife either (I tried a long time ago ...) .

Bob,

I am convinced now---notch 'em, sister 'em, and for extra overkill, add more bridging. A huge weight off my shoulders. Thanks for the initial Kerdi pointer, too. What a system!

Is Nobleseal mentioned by Eric more or less equivalent to Kerdi? They do have nice CAD drawings on their site, too (calms my wife down, you know).

Thanks again to everybody.

Alex

[muskymike]

Hi Alex, welcome! Here is a Kerdi shower I did with Ditra on the rest of the floor. Click this