Okay-- a couple of things. First, the poly's not necessary between the foundation and studs. Secondly, I missed the part about the shower pan being the concrete floor. That shouldn't be done. The ONLY way you could get away with it, as far as I'm concerned, would be to set a Kerdi drain in the concrete, with the "halo" flush with the concrete, and then the floor could be Kerdi'ed to the walls, along WITH the walls. THEN it would work. Of course, the concrete in that area would have to be sloped appropriately to the drain (1/4" per running foot from the furthest point away from the drain) But to just expect the slab to act as the pan with no waterproofing, and not expect to have problems would be fooling yourself.

First, I'm going to regurgitate what Tom and Bill already wrote, but wrap it in my own words. Densarmor is a paperless gypsum drywall product. No paper face means mold and mildew can't dine on the cellulose/paper face of the product, because there is no paper in the product. It's primary use is in places like basement remodels. Naturally damp locations, etc. The downside of the product? It has fiberglass in it, so it can irritate the skin during installation. The paperless surface does have a slight texture to it, and that bugs people in terms of how it takes paint. Obviously, don't use paper (cellulose) tape when installing it. Back to your question. If you use nothing behind the cement board, then water that gets through the tile/grout to the cement board can then get through the cement board to the framing. Sounds unlikely, but it happens unless you use a topical membrane like Kerdi. But that's for another thread. So in a bathroom, you need to use either 6-mil poly or #15 tar paper between the cement board and the framing. This is not for use as a vapor barrier, but as a drainage plane. Any moisture that gets through the cement board will now condense and run down the drainage plane, or it will eventually dry back out through the cement board into the shower. No arguments there, that's the way it is. The tar paper really isn't a vapor barrier. A retarder, yes, but not a barrier. The poly is a vapor barrier, so since you want only one vapor barrier in any wall assembly, then slice the kraft facing on the existing fiberglass, or whatever vapor barrier you now have on those walls. Done. Now you only have one vapor barrier in the wall assembly. Remember, we're talking two things here...a vapor barrier AND a drainage plane. You need a drainage plane between the cement board and the framing, it needs to cover the insulation and the framing. You want a vapor barrier in your exterior walls, but the vapor barrier only needs to cover the insulation. The kraft paper facing on fiberglass batting can not be both. But continuous 6-mil poly that covers the insulation and the framing, can. The 6-mil poly that you install will be the drainage plane AND a vapor barrier. But you can't have TWO vapor barriers in a wall. So by destroying the one you now have, the new poly becomes both. Repetitive, yes, but this is to reprogram you after the attempted brainwashing by the folks at HD. In the wet areas of your bath, only use cement or foiber cement board as a tile backer. No drywall, no greenboard, no DensArmor (all three banned by the building code), no Denshield (technically allowed, but I don't recommend it), just cement board (Durock, Wonderboard) of fiber cement board (Hardie). Personaly, I prefer Durock or Wonderboard over Hardie, but that's just me. Hardie is a fine product. Outside the wet areas, use what you want. Densarmor, greenboard, whatever you want. Your choice. Mongo

Go to the owner and put a stop to this crap immediately. Sit down with him, explain everything you've just told me, and let him know that you're not going to accept "thrown together" work just because his installer and salesperson are having a pissing contest, and the installer is pressed for time. The tub REQUIRES either a vapor barrier behind, or waterproofing over, the backerboard. End of story, no questions asked. You will not give him another dime until it's so. You'll also not give him another dime until all work is completed to industry standards, and you've got someone on call with both a TCNA handbook and ASNI 108 and 118 to guide you on what is acceptable and what is not. Tile setter works on installing backer boards since we have no tile. He works maybe 5-6 hours a few days and the bathrooms are ready - minus the shower pans (2). Also, if he's NOT using a surface waterproofing, I'm curious how he's putting up the backerboard BEFORE the shower pan. He started the walls on Monday, starting around the tub from the top down. I would have thought he would start from the tub up? Doesn't matter. Personally, I also prefer to work from a level line down , because I can't count on existing surfaces to be level and plumb, so I'd rather go from a line I KNOW is level, and then cut in the abutting surfaces. However, no matter if you work from the bottom up, or the top down, you KNOW what your pieces are going to be before you start, and make sure you won't have any slivers. You adjust your level line to MAKE SURE you avoid it. As for the 6600.00 for the master bath tile, You'd have to have an incredibly big bathroom with all kinds of custom touches to it, or located in a penthouse across from Central Park West to justify that price to me. But you've agreed to it, so you have to honor it. That IS, however, just one more reason why they should be bowing to any request you make.

These are the ones I am familiar with: 1. Perm-A-Barrier VP î Air/Vapor Barrier fluid applied synthetic latex rubber membrane as manufactured by Grace Construction Products. a. Primary Air Barrier Membrane: One component elastomeric membrane, spray applied. 2. Air Bloc 31 as manufactured by Henry Company Inc., Cold Stream Road, Kimberton, PA 19442. 3. Sto Guard Assembly: manufactured by Sto Corp., Camp Creek Pkwy, Atlanta, GA 30331 a.Sto guard mesh for joints and flashings b.Sto Gold Fill for joint treatment. c.Sto Gold Coat for the membrane 4. PROSOCO R-GUARD Assembly: provided by PROSOCO, Inc., 3741 Greenway Circle, Lawrence, Kansas 66046. a.PROSOCO R-GUARD Tape for joints and flashings b.PROSOCO R-GUARD Fill for joint treatment c.PROSOCO R-GUARD Spray Wrap for the membrane I have used the WR Grace product on CMU back up in a brick cavity wall for a college dormitory but I like the STO system for residential construction because it can be applied by anyone with a roller.These products will someday be the only weather/air barriers used in houses when the manufacturers finally decide to actively market them for that use. Sorry, I don't have any cost data at the moment.