phylhl-- Let me guess-- you're in Mass.? Copper pans, are, for all intents and purposes, outlawed just about every place else. The only reason they're still allowed in Mass. is because the plumbers union makes alot of racket to KEEP them legal. They've been outlawed elsewhere for three reasons. First, they're usually flat bottomed, and as TileTech alluded to, the pan membrane must be sloped so as to make sure all water that gets into the pan goes to the weep holes. Which brings me to point 2-- there are NO WEEPHOLES in copper pans. Any water that gets into the pan stays there, making for the perfect breeding ground for mold, mildew, and bacteria. Lastly, over time, the lime in the cement used to form the shower pan will corrode the copper, and I don't have to tell you the mess that'll make.

Then I'm thinking of a different product. Just to confirm I did a quick google and found this: "Bonsal Co. offers the ProForm Shower Pan, a tile-ready waterproof pan. The shower pan will not retain moisture. Installation requires a glue connection to a standard PVC drainpipe. The pans are pre-sloped to drain and tile can be applied directly to the sloped pan." So it sounds like we have two different products in mind. If he's not using Bonsal's ProForm pan, which is a preformed pan, then the only other thing I can think of off the top of my noggin is he's using B-6000, which is a liquid topical roll- or trowel-on membrane. If he's applying the B-6000 to the flat subfloor, then packing in a sloped base of mortar on top of the membrane, then tiling on that, that does not meet code. And if code doesn't not apply in your area, then I'll just say it doesn't meet the basic standards for constructing a shower. In this case the B-6000 would be considered the "membrane" or the "liner". Go back to Bill's first post and read what he highlighted in bold about the liner needing to be sloped. If he's not using the Bonsal ProForm pan or the Bonsal B-6000, then I have no idea what he's using. I'm not sure if Bonsal markets a traditional 40-mil pan membrane. But if they do, that should be sloped as well. Mongo

"and im guessing you do not buid tile showers youself and have to navigate inspections" -- Guessing is what got you back-peddling in the first place, (and changing/ deleting your posts after I show you that you are wrong). You would be hard pressed to find something that I have not personally gotten a permit for, and passed the inspections. "as such It makes sense I confused you again." -- You are not confusing me. At best, you are confusing the issue at hand and the OP's original question of slope. I would be more concerned with this statement; And, how they had planned on getting the Oatey liner even 2" above the threshold, and behind the Durock without taking it all off. BTW, how much of the bottom edge of the Durock do you usually leave flapping in the wind without screws in order to not screw through that extra 6" of liner? The Durock also has to be screwed per MFG instructions. When trying to one-up the code, make sure you are not shooting yourself in the other foot.

"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.