Gotcha. I'd say do the shower floor just like it was a nobelseal shower floor. Run the membrane across the floor and up the wall studs/blocking to a height about 3" above the top height of the curb. Check into that 3" minimum, I think that's what Nobel recommends. It can be nailed or stapled to the studs at the top edge of the membrane. You can detail the corners as they are supposed to be. The thing to watch out with when using thicker membranes like Nobelseal is that several overlaps can cause the bottom edge of the backer board to get "kicked out" into the shower if the overlaps will be trapped between the backer board and the wall framing. Regardless, there are several ways to detail the corners, you can fold them, or cut and overlap, or use preformed corners. Or tuck the membrane into the corner. With tucked, just make sure that the tucked part doesn't flop down in the corner, you want the top of the tucked edge to stay 3" above the flood plain, or 3" above the top of the curb. Each corner method has its pluses and minuses, see which is best for you based upon your situation. That build-up when overlapping, though, that's why you'll see references to notching wall studs, etc, when using thicker membranes. Anyhow, after the floor membrane is installed, install your backer board on the wall. Hold it about 1/4" or so of the floor. Fill and seal that 1/4" gap with a Nobel sealant or its equivalent. Now if you were running nobel membrane on the walls, you'd run it on the walls and butt it to the floor membrane, sealing that butt joint with a bead of nobel sealant. However, since you're using Kerdi, you can do one of a few things: 1) Install the wall Kerdi just like it was nobelseal membrane, butting the Kerdi on the wall to the Nobel on the floor, and seal the wall-to-floor membrane joint with sealant. This might be the best way due to the uncertainties about overlapping Kerdi and Nobel that I'll talk about in a bit. 2) Run the wall membrane down the wall and lap it onto the floor membrane 3" or so, thinsetting the Kerdi membrane to the nobelseal on the floor. If you do this though, you might need to run a couple of beads of sealant between the Kerdi and the nobel where they overlap on the floor. 3) Any of the other typical "Kerdi" options, which would be running the wall membrane down onto the floor like in #2 above, or using Kerdi band to seal them, etc. Again, though, where Kerdi overlaps Nobel, you might need a couple of beads of nobel sealant. Regardless of which you chose, I'd call Nobel and Schluter and run the options past them. I think option #1 is pretty straightforward and safe. My concern is that while a Kerdi-Kerdi overlap can be made watertight with a 2" overlap and thinset, Nobel requires nobel-nobel overlaps to have two beads of sealant to make that overlap watertight. Essentially, the Kerdi-Nobel overlap is untried and untested, so two beads of sealant might be best. But it's still untested. However, (and it's a big however) the overlap really doesn't really have to be watertight. With the nobel floor membrane running several inches up the walls, it's like a traditional CPE shower pan. There's your waterproofing. All you really need were you to overlap Kerdi on to Nobel is that the overlap not delaminate. With thinset being able to adhere to the fabric of both membrane, that shouldn't be a problem.

Bill, thank you for your response. I'd always thought of caulk as not being much of a good fix for most things, because it never seems to hold up well or for long. Wouldn't this be the case here, or is tile different, or is there a special caulk used with tile that you're referring to that is more durable that that used between a tub and a tile wall? After thinking about this some more, it's clear that I need to consider Plan B and do the L configuration if it's to work at all because of the tile situation. So the next question is: --How far back would he likely have put the mud base? When we remodeled our old place, the mud went to the wall at the back of the vanity. --Is this what is normally done? If the tiler slapped down 12 x 12 sheets of the 2" tile, there probably is about 5" under the existing cabinet. If the mud base goes to the back of this vanity, that would give me another 13", giving me ~18" total depth, and I have enough leftover sheets of tile to cover this. --So if the mud base is there, shouldn't we be able to lay tile on it? --If the mud base is too rough, can it be either ground down in the high places or filled in with the setting compound? --How deep can the setting compound be and still do its job properly? Thanks for whatever clarity you can provide! Anne

Just to add, I know that Bill, Mongo and anyone with a real clue doesn't care for the Schluter edging, but I did end up using the Dilex EKE for the joint between the shower pan floor and the walls, and no caulk needed there. It is a very low profile profile, and you just grout to the edges, as the thing itself acts as the movement profile. I am hoping it lives up to the claim of maintenance free. I am not completely adept (and DH is definitively NOT) at caulking technique, although my joints in other spots did improve as I went along, I realized that if I wanted a nice clean corner, that was the way for me to go. The really talented folks may not need to use it but I don't count myself among them. I think it looks nicer than any caulk job I could have done, and the "matching" caulk did not live up to a color match- I used TEC, Birch, and the matching caulk was downright GRAY! So, the Dilex actually comes closer!

First, we want thinset used under all tiles, this would include, marble, granite, ceramic, travertine and marble mosaics. This needs to be white because the color can shadow up through the travertine and the light marbles. Correctimundo. We are going to go with epoxy grout (I've read the pro's and con's). Does this change the rule that you use caulk at the intersection of a wall and floor (or upright tiles to flat tiles or countertops?) not even a little bit. If anything, it makes it even MORE necessary. That caulking's there as a movement joint-- not as a moisture barrier. Now, if you grout that joint with epoxy, you're not going to stop the movement. What's going to happen instead is that the movement will find the weakest part of the wall to transmit through, and being that the grout will now be stronger than the tile, guess what's going to crack? All grout lines are to be 1/16th (is that a penny spacer or do them make spacers that thin?) All are to be unsanded. yes, they make them that thin, but in the case of any natural stone on the walls, marble wedges would work even better. As for the unsanded part, there's only one kind of epoxy, and the filler used in it is much much finer than normal sand in sanded grout, so it'll fill into the smaller joints very easily.