For your shower you need 2" of vertical between the top of your drain and the top of the curb.

In a curbless shower the top of the curb essentially becomes the flat part of the bathroom floor.

Code also requires the slope of the shower floor to be between 1/4" per foot and 1/2" per foot.

Using the maximum floor slope allowed by code, to get the 2" vertical you'd need 48" of run, which is what you have on your short dimension. Since you want one of the long 60" walls to be open to the room, the drain would have to be right up against the back 60" wall.

You can place a conventional drain there, centered on the back wall, or even a trough drain if troughs are allowed in your locale.

You can make the preslope with conventional deck mud instead of one of the preformes Kerdi trays, then Kerdi right on top of the sloped deck mud.

Actually, the wet room isn't a bad idea, but if you're going to Kerdi the shower, continue it out into the rest of the room. Two different membranes could be problematic where they meet.

Sump pump. :-)

So mongo, in you description of the 2" for the drain, does that effectively mean that you raise the entire bathroom floor by 2"? If so, I may have to rethink my curbless shower downstairs and just sink the shower floor a couple of inches. Still sort of curbless but not seamless. I can't lose another 2" of head height as the basement bathroom already has a 7ft ceiling due to a huge, unremovable bulkhead that Joel says apparently holds the plumbing/electric/utilities royal jewels of the house or something.

pirula,

If starting from scratch in new construction, I drop the shower floor lower than the bathroom floor when framing (wood construction) or when pouring the slab.

If remodeling, sometimes the shower floor can be dropped. But it's a pain, and it really depends on how the floor joists are running and their loads.

Going the other way, it isn't uncommon that the shower floor remain at the original elevation and the rest of the bathroom floor is raised. But that can create problems on its own.

Another thing I've done is instead of a typical curb, I'll make the curb a "hump", or ramp up the bathroom floor to get the required elevation. The bathroom floor keeps its original elevation, the hump/ramp is gradual enough that it can be rolled over in a wheelchair, and vertical enough to give you proper slope and elevation within the shower. The hump curb can work well in a medium to large bath, but can be awkward in a small bath.

In basement remodels it's not uncommon to cut out a section of slab where the shower will be, then re-pour at a lower elevation. For any readers with slab-on-grade construction don't cut into the slab if it's a post-tensioned slab.

So there's a lot of "it depends" buried in that reply.

Thanks very much Mongo.

I had just had Joel read this and he says he'd already thought of it and was planning your option 2. The one that's a "pain." LOL! I had no idea he'd already though this all through. I should have known though. It's basement so I suppose he can go almost as low as he wants.

Ivette

How did your curbless shower turn out? Can you share some pictures?

Waterproofing a bathroom floor is simple procedure with your Ditra mentioned above. Ditra when banded with Kerdi cloth is a waterproof surface.

We heat our bathroom floors on most jobs and then cover these cables with Ditra - In the wet zones and splash zones Kerdi cloth over the Ditra makes for a great tilling surface. Just because we only get one chance at a waterproof product I like a little liquid waterproofing over the seams for overkill.

There is no issues combining Ditra and Kerdi.

A curbless shower should be built with a 2" drain line. Here in Vancouver our local code dictates that we can't drill any hole larger than 2 1/4" through a 2"x10" (9 1/4" actual) floor joist - and that the hole must not be within 2" of the edges. Check with your tile setter your codes, check with your plumber and check with your builder - you may be shocked to find all three of these people don't know the code or even have a code book with them.

This code is a very key number as it affects the position and placement of your drain and where your 2" P Trap and 2" pipe can travel. Here in Vancouver notching joist is not allowed unless the joist is top notched and the notch is less than 1/3 the depth of the joist and located with 4 1/2" from bearing point for a 2"x10" joist.

Take a trip down to your building department in the early morning and catch your inspectors at the office before they travel out for inspections. Ask them how they would like to have the curbless built. They may tell you you can't or you need to produce a drawing.

3 Years ago I met with strong resistance when designing a curbless shower. I was working in Vancouver and the local inspector said "I'm sick of this question!" - think about their jobs (the inspectors); they have to check all construction and insure it's safe and meets code. Countless trades people and clients want to build new things and have no clue how to achieve them.

Try going into the inspectors office with drawings and material choices. Show a simple cross section detailing pitch and products used. A request like this is night and day different from someone just saying "Can I build a curbless?"

I hope your bathroom went smoothly - having your guy willing to read and train online with you is a good sign.

Regards,

John Whipple

"When it's perfect. It's good enough."

Hi. Any drawing of this job? I am getting ready to re do my bathroom and I am installing a 36x60 walk in shower. I can't drop the floor joist 2 inches to fit the pan. Any ideas? ( visual images would be great). Thanks