I have built two curbless showers with in the past year and a half. Both where built using Ditra, Kerdi and Red Guard. I have been having more and more clients ask for trench style drains and have spend about 8 months researching these beauties. Quick Drain USA has a nice channel (trench) drain with excellent tech help and a wonderful website. ACO now imports to North America from the UK and I have found that their drain can fit on top of a Schulter drain rough in (this can not be done without modifying the stock unit and I'm sure it will void any warranty). All that said I should have much more answers to this specific question in roughly 3 months time. The more I look at the trench drains and the more we explore the options it creates it's no wonder the channel drain is the hottest look of any new shower. As far a a nice clean looking curbless shower with a simple Kerdi Drain the entire bathroom needs to be waterproofed. Toilets should not be placed too close to the shower entry because a typical floor mount toilet is the biggest weak link in a wetroom floor. A better option is installing a wall mount toilet or small covered curb (i.e. pony wall, glass block wall, frameless glass on low curb) that separates the toilet location from the wet zone. Make sure you pipe your new curbless with at least a 2" drain line (with properly sized vent line) your design and polumbing package might need a 3" drain line so even though you want the new channel drain you may need to install a standard drain in addition to the floor drain. It's hard to teach an old dog new tricks - Push your builder or tile guy to research harder. Be prepared for extra costs. Framing changes, concrete work and structural engineers may need to be used. I designed my last two around standard framing and raised the transition from the hallway to the bathroom to 3/4" - 1" (Solid hardwood reducer at doorway) and pitched everything back to a single Kerdi drain.

We LOVE our curbless shower. It WAS expensive. We have a pier and beam foundation. I don't know exactly the inches but I learned that because our shower was 5 X 5, this made it so it could be identified as an ADA compliant shower - no larger or smaller works for this label - must be 5X5. Once you are ADA compliant, rules can change and in some case are more lenient as far as the floor slope. You need to check your local code. Don't want that wheelchair toppling over, I guess. We have a linear drain on the far wall away from the shower opening (3 ft wide) and which always drains well with no water coming out the shower opening (we chose not to put in a door and not having a door adds SOoo much wonderful ambience, it is great) and though I don't know inches precisely, there is no way it is a 4 inch drop on the tile floor. Maybe beneath, it took four inches but I doubt it since no "shower pan" as such was used, I'm pretty sure just Schlueter waterproof sheets/products were used. We also had radiant floor put in to keep any possibility of drafts down in the winter. But I'm obviously not into the details on this very well and got help from Mongo on some of this so I will defer to him on the contruction details. But I would like to say most importantly that the 5X5 is a perfect size and we wouldn't really get any more enjoyment from an 8X5 but your mileage may vary. I can be using the fixed shower installed on one side of the room and easily reach across to the hand held shower installed on the opposite side of the room at the same time. Room enough for two. AND turn on the rain shower in the middle. Fun, fun, fun. And because ours was 5X5, we had space to put a closet on the other side of the wall of the shower for use in the adjacent room. Closet also gave us a place to install the Moen idigital shower valve and access panel. This really allows the shower walls to have a clean look and adds even more fun to the whole process of showering, IMO. It was quite expensive but if we had to make the choice again, we would still choose the curbless. But make sure your contractor has experience cause I definitely got the impression you want someone who knows what they are doing.

Mongoct/Live Wire Oak, Thanks for the replies. Here's a photo I took right after the hot mop was done. You see it terminates at the outer half wall surface with a 'lip' maybe 1" tall (I didn't measure it so just guessing). So that centered tile in the entry sits above that and during a normal shower the water line (water that splashes over the drain to the door) doesn't go past about halfway the thickness of those half walls or doesn't go past the glass door that's centered between those half walls. So if I understand what you're saying about the capillary break, the tiler should've physically separated the thinset/mud under the entry area tile by creating a physical divider barrier to separate it from the thinset/mud under the rest of the tiles on the bathroom floor? I'm picturing a thin vertical layer of sealant (or membrane) from the bottom of the tile surface through thinset all the way through the mud down to meet the hot mop 'lip'? That would then form a barrier and force the water that gets under the tile to stay in the pan and go back towards the drain. I'm still trying to get a feel for how much water could be sitting under my bathroom floor (worst case) or if it's limited to a few areas of damp thinset due to wicking that are showing up as dark grout spots (best case?). Relative to the amount of water that seems to be making it down the drain, how much water are we talking about that could be wicking out through the thinset/mud/grout? 10%? 20%? 50%? How long does it take for the water that eventually sits on the concrete slab to evaporate or absorb into the slab itself? And what damage would this cause long term assuming the water never makes it to any wood?

Jackie, You started in the right place. Ask questions on this board. There are a lot of resources available from the experts and those who have been on both sides of the hammer. We will tell you when it's something to really worry about. Respect is a two way street. Hire the best people that you can find. Let them do their job. Monitor what they do. Question things if you don't understand them. Ask if there is an alternate way of doing things. Be flexible. Trust, but verify. Understand that the really good professionals are always busy, but never too busy to answer a sincere question. If something doesn't seem right, ask about it. Don't be afraid to ask why? Question every one of your decisions by asking if there is a better way to complete something? When you are asked to make a decision, give it quickly and decisively. If you don't know the answer, tell them you don't know or don't understand. If you encounter something that you don't like, and you will, talk about it with the GC. Let your GC handle the subs. It's his job to yell at them, not yours. That's what they get paid to do. The GC gets paid to answer to your satisfaction unlimited questions. Try not to bother the subs too much. Always be friendly. A sense of humor will go a long way to get through this process.