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."

With a curbless shower, I see two issues you may be facing. If he is planning on using a traditional rubber liner, a pre-slope under the liner is required. This slope is a minimum if 1/4" per foot from the drain to the farthest wall. In this case, I assume that to be the entry. I fugure that to be about 2 3/4" higher at the entry than at the drain. The rubber or vinyl liner sits on this and a FINAL mudbed is then formed over the liner. As you can see, there will be issues with no curb and how you'll terminate the slope to a feather edge at the entry. I don't see how that can be done. The other issue is with the liner itself. I see no way to attach it to a mudbed that would have to end at a feather edge. These liners are designed to go UP the vertical walls about 6-8" and nailed into place. Having built these before, scrap the liner and use the Kerdi. It's a bulletproof install, you only need ONE mudbed as the material is bonded directly to the mud and you can generally extend the Kerdi six or eight inches into the bathroom for a bit more insurance. On one hand, yes...it's a bit more cost, but realistically, it's also a shower you'll probably never need to repair or replace. The Kerdi is under $1.40 sq/ft. Their drain will run about a hundred bucks. On the other hand, you only have the cost of one mudbed, you eleminate the vinyl liner, as Kerdi is completely waterproof, you can save by using standard drywall in the shower as opposed to cement board. This is what Schluter recommends. Bottom line is that you'll pay a little more but get a far superior shower. If your tile installer isn't comfortable or familiar with Kerdi, find one that is. Here is a link that might be useful: Kerdi Shower Handbook

Thanks so much. I now understand so much better. Our foundation is "pier and beam" but as you indicate, that is still probably not or may not be a simple task to lower. But now I see that if there is a linear drain and you luck out with the door to the shower in the right place relative to the joists, the linear drain can very likely simplify the task (in addition to making things look sleeker). Our shower will be 5 X 5 which means the slope would be even easier to implement without obvious detection. Though I now see why some documentation I've read indicates a "secondary drain" outside the shower is nice to have. If the water in the shower overflows past the linear drain into the room, the secondary drain can cover that but then with the secondary drain, you are faced with needing to slope the floor in the main part - i.e. lowering joists or maybe finding a place between joists - another engineering task. I also now see why what shower fixtures are chosen and how to implement makes a difference here. If your fixtures (i.e. running hand held plus standard shower head plus rain shower simultaneously) allow for a LOT of water simultaneously, then the likelihood of linear drain not being able to handle it all increases, thus likelihood of water going into main part of bathroom increases (if there is no curb or door that will stop it). If you have a recessed center (regular) drain) in your curbless shower, then the recess can be like a shallow bowl that can hold some of that water before it runs out of shower. Hmmm - lots to think about.

You CAN chose a curbless shower pan if you get a solid surface one. In other words, if you get one that is made from a Corian-like solid surface that is water proof, leak proof, and mold and mildew proof - all unlike a tile and grout shower. There is a place in Oregon that makes custom solid surface shower pans that will probably make your size. They are called Grifform. I am getting a Transolid ADA 37 3/4" x 63" shower pan. It has a trench drain at the front edge with a larger round or square drain just behind it that they cover with a piece of the solid surface material. This shower pan is installed on a flat subfloor, on a bed of thinset mortar. Then wall substrate is installed on the walls so that it allows the tile or solid surface wall material to be situated inside the flange on the shower pan. Once the gap is caulked, the system is waterproof as long as the wall material is waterproof. Grout is not waterproof, so don't let your tiler tell you that your walls don't need waterproofing. Green drywall is not waterproof, but tilers use it every day for a substrate for tiling a shower. That is why I refuse to have tile in my shower. I won't scrub grout. And I don't trust tilers. Many of them don't follow the procedures of their own profession! My tile is going on my room walls, where it will not be getting wet and will have no reason to get moldy. I have joint issues and I can't scrub.