We're installing a new one piece shower unit in a "being-finished" basement. The bath area is pre-stubbed for the toilet, sink and shower. I have broken the concrete patch over the shower drain pipe and then got a drain collector similar to this Oatey (link to pic below). I also bought the elbow, p trap and an extra length 2 inch pipe yesterday.
http://www.oatey.com/graphics/products/drains/42050.gif
Correct me if I'm wrong here.......
(1) I get the elbow, p trap and 2 inch stub test fitted and figure out where I want it to end up by hauling the shower over it and seeing where/how they match up. Trial and error to get proper placement. Once done, I'll make markings on the fittings with a Sharpie so I can align them again when using the pipe cement to put them together permanently.
(2) Cement elbow to drain pipe and then p trap to elbow using markings previously made for proper alignment. Finally, cement a length of 2 inch pipe into the open side of the p trap. The stub of 2 inch pipe cemented in place out of the p trap will initially be sticking up about 4 inches above the concrete floor grade before trimming. Test alignment again by putting shower unit in place (without drain collector attached) and making sure that the 2 inch stub is sticking up where I want it.
(3) Once satisfied that the piping and trap are where they're supposed to be, I mix up some quick-crete and pour into the floor cut out (pea gravel in the bottom first), smooth it out and let it set up overnight.
(4) I attach the drain collector to the shower pan by taking off the nut, washer and rubber gasket. Drain goes into shower pan from above and the rubber gasket, washer and nut go onto the bottom of the pan (in that order) - tighten into place after setting a bed of silicone on the top side for the drain collector to snug down into. Wipe off excess silicone after tightening and let set up over night.
(5) The next day after drain and cement are set up, trim the stub to the proper height to mate with the inside rubber gasket in the drain collector and ease the shower unit (with mounted drain collector) on top of the 2 inch pipe stub making sure to seat properly (Check for level, shim underneath unit where needed). I tested the 2 inch pipe and the drain collector, they mate up pretty darn tightly but the weight of the shower unit should help push the collector down onto the pipe stub. (I read something that said if it's too tight to use some mild soap like Ivory to help it seat and it will gradually wash away with the draining water. Is that OK to do?) One other question here: The length of the rubber gasket on the inside the drain collector is about 1 to 1.5 inches......how close to the top of the rubber gasket should the top of the pipe stub be when the unit is seated firmly? In other words, looking down the drain (when the shower unit is seated as far as it will go onto the stub and resting evenly on the floor), how much rubber gasket should I see before the top of the drain pipe begins? I guess I figured a quarter inch but that's speculation.
(6) Checking level again and adjusting shims if need be, attach shower unit to the studs surrounding the unit with drywall screws and then greenboard around it.
Anything I'm missing?