Steve, I've used the Kerdi Trays, and while they are easy to use, there's a little weirdness to them. Sort of like a floating floor, they can sound a little "hollow" when water hits the tile, but that can depends on the shower head used and the type of spray that comes out of the head. When I've used the Kerdi Trays to advantage is when I had multiple showers to do at once. I framed the showers a uniform size and down went the trays, boom, boom, boom. Done fast. I do prefer a mud bed versus using the Kerdi Tray. But that is simply my opinion. Nothing wrong with the trays. Mud slopes aren't horribly difficult. Just set your drain elevation. Set your perimeter wall mud height. Then fill in the in-between part. The beauty of deck mud is that it's lean enough that you can shave it here and build it up there while you work it. For your first attempt consider having a few screed boards or straight pieces of scrap wood of varying lengths that you can use to screed the mud or use as sighting boards to keep the mud flat as you work the slope from drain-to-wall. There are also commercially available sloping kits, essentially sloped screed boards. Or you can cut your own tapered pieces and use them to help you hit the slope. Humps in the sloped floor can be shaved down. If you have a divot/depression, do not accept it. Fill it in prior to kerdi-ing the sloped floor. If the "discouraged about Kerdi" comment indicates a dissatisfaction or trepidation with the Kerdi product itself, there's a hybrid approach that has been discussed a few times using a sloped mud bed, a kerdi drain set in the mud bed, cement board on the walls and HydroBan (instead of Kerdi) to waterproof everything. Put a few beers on ice. You'll be ready! Best, Mongo

Thank you Mongo for the explanation. It came just in time. I just had two other tile guys come in today and YOU WILL NOT BELILEVE...okay you pros out there probably will believe...what I heard today. When I mentioned what the original installer said, I think David you called it laziness, Mongo you called it uneducated. Here's what I found out. I had two additional tile installers out today. I was still not hearing what I wanted to hear when I asked for details about their process, esp. regarding the moisture barriers behind the cement board and the membrane on the shower pan floor. The last guy seemed very knowledgeable and I said to myself, I've got to come on out and just point blank ask because I am not getting anywhere. He said the same thing about cement board as the previous guy, but at least HE mentioned, taping those seams of the cement board with a mesh strip and thin setting it. So far so good. I asked about some other moisture barrier for the framing before cement board. He said they use a poly liner thing behind the cement board on the exterior wall. They don't normally do it on any other wall but they could... no problem. He mentioned some of the new boards that are lighter and made of foam, but he said they don't use them. Same deal, unproven and he would prefer cement in his own home. We talked about the shower pan membrane and he too talked about sand mix, membrane, build slope and tile. I finally came out and said, "I read somewhere the membrane should be put on a slope or something." He said we generally do it flat but what you are talking about is the pre-slope. He KNEW ALL ABOUT IT! What he said next floored me. He said yes in the Highland Park area we do a preslope. They have million dollar homes there. Not to say your house is not nice, but that area has more restrictions. Mongo, David and Bill...he described the steps just like you said...I guess my less than million dollar house didn't warrant the "correct" installation technique. :-( He even said why it is better to put it on the preslope, but I guess "cheap" houses don't get the extra steps. LOL I asked him about the membrane placement and he described what I had seen in the Harry Dunbar website. He did say he goes up about 8" on the walls, not 12 inches. He did say doing the preslope would make the shower pan area higher, but I told him I did not have a problem with that as long as the membrane was on the preslope. He did not have any problem doing it, but I am sure it will be reflected in the estimate he gives me. :-( Thought you guys would be interested in what I found out today. Thank you so much. I definitely will not be using the first guy.

I m a little confused by the description of what each guy is doing. Whatever they do, make sure the floor membrane itself is sloped to the drain. Iy's a code violation to install the membrane flat on teh subfloor with sloped mud on yop of it. "One mud floats the entire shower after pan and cement board are installed." Is this guy floating mud directly on the cement board? Floated walls are typically (at least in my experience) tar paper and then expanded diamond mesh on the walls, with the mesh wrapped through the corners. Then the walls get floated with mud. A tile backing surface like that with mesh wrapped through the corners will not crack on the wall-to-wall corners, so the corners can be grouted. If you're looking to avoid corner cracks, you'll have better success with a fully floated shower that has mesh wrapped through all corners, versus tiling over a lightweight tile backer board like cement board. I do like Shluter's Kerdi membrane, as well as other surface-applied membranes. They can be installed over cement board, and even over a floated mud wall. I think every tiler should want to control the process from studs-to-tile. The tile can only be as good as what it goes over.

"Oatey" usually refers to a shower pan liner. Sloped mud (preslope) gets installed over the flat subfloor, the Oatey goes over the sloped mud, so now the membrane itself is slope to the drain. Then more mud goes over the Oatey and tile goes on top of the second layer of mud. Wall waterproofing will be independent of the Oatey liner. "Kerdi" is a surface applied membrane, most often it comes in sheet form. Kerdi can get applied over a sloped foam Kerdi tray on the floor (or to save money, omit the Kerdi Tray and use sloped deck mud), and if your shower walls are already drywalled or covered with cement board, Kerdi membrane can be applied directly to the drywall/cement board on the shower walls. Tile goes directly on the Kerdi. With Oatey, the Oatey liner on the floor combined with (for example) 6-mil poly sheeting behind cement board on the walls will usually give the least expensive installation. Many showers have been built this way and properly detailed, they perform well. The downside? On the walls the tile, grout, thinset, and cement board can theoretically all get wet. On the floor the tile, thinset, and top layer of deck mud can all get wet. Once the mud base wets, it usually remains moist over the life of the shower. With Kerdi (or most any other surface applied membrane), there is less wetting of the shower structure. Because the tile is adhered directly to the membrane, the only thing that can get wet is the tile, grout and thinset. You can usually save money using Oatey and 6-mil poly. You can better control moisture with Kerdi (or another surface applied membrane). You can save money over a typical Kerdi installation shower package by not using a manufactured Kerdi Tray on the floor and instead using sloped deck mud.