Shower drain - order of events

[djohnson]

I am redoing my shower stall. I tore out all of the cultured marble. I cut out the old drain and the all of the water-damaged plywood that was underneath and around the shower stall.

I have bought a Oatey adjustable drain for tile and pan. It is a PVC unit that solvent welds to the drain line.

(Like the one in this document (http://www.oatey.com/shower_drains/lit/Shower%20Pan%20Liner.pdf) )

This is on a second floor and there is no access to the floor from below (without tearing up a bunch of ceiling on the first floor).

I am not sure about the best way to put it all together. If I put my subfloor down with a hole in it just big enough for the drain itself, I'll have no way to hold the drain pipe as I solvent weld them together.

I was thinking that I could put my plywood sheet down, but with about a 12" square cut out of the plywood above the drain pipe. I could assemble the drain and pipe and then use the piece that I cut out, cut it in half, cut a 1/2 circle in both of those pieces. Then, I'd have something to fill the void and support the drain.

Obviously, I need to use 2X4 blocking under the subfloor to tie the cut pieces into the plywood sheet.

Is this the best approach?

In case I explained this all poorly, I'll attach what the 12" peice would evolve into and a side view of my plan.

[djohnson]

Here's the images.

[GrumpyPlumber]

I saw "marble" and "shower drain".
One thing I'll say...IF you're replacing it with more marble...DON'T use plumbers putty on the drain flange.

[frenchie]

Is the drain pipe (underneath) not supported? Because it should be...

In which case, it doesn't matter whether you can hold the pipe it while gluing your drain locking ring.

?

[djohnson]

Here's what I am doing:

I am doing travertine in a "pinwheel pattern" where you have 1X2 tiles around a 1x1 on a peice of mesh. I plan to do something very similar to the illustration in the Oatey document linked in my original post. So above the subfloor will be preslope, fiberglass or membrane pan, mortar, and then the tile.

The drain flange will be solvent welded to the drain pipe and then I believe that you use silicone caulk between the shower pan and the drain pieces. I assume that you also caulk between the tile pieces and the top of the drain. (I haven't gotten far enough along in the project to memorize those steps). So, plumber's putty isn't in the plan, but I'll leave myself open for correction about the caulk and what not.

As far as the drain pipe support goes, this is over a strange area of the downstairs where ceiling is lower than it is everywhere else to allow for duct work and what not. So, when they ran the drain pipe, it goes under the trusses. There is a metal strapped nailed to the bottom of the trusses to brace the drain pipe. It is about 2 feet away from the U trap. About a foot and a half behind the metal strap is a Y connection where it joins up with the tub drain and flows off into the abyss of the house. The run from the trap up to the floor will total around 12-14".

If you push straight down on the pipe, it will give 2" or so. I haven't cut the final piece of pipe that runs from the trap up to the drain, I could make it long enough to account for that give. however, once my drain is attached, it will naturally want to then float above the floor slightly rather than resting on it.

Do I need to figure out a better way to secure it so that no give is present?

All of that gives me a second question... when I am choosing where to locate the hole in my subfloor for the drain, is it important that I make it perfectly so that no stress is on the drain pipe at all? When I dry fit everything, the way that the pipe comes up makes the drain a little out of level with the floor. If I pull the drain about one inch in one direction, it will level out. I figure that having the drain level is critical, but I didn't know if that's ok for the pipe or not.

[geniescience]

.... If I pull the drain about one inch in one direction, it will level out. I figure that having the drain level is critical, but I didn't know if that's ok for the pipe or not.sounds like you might want to cut a bit, if you have that much give. Too much play.

The top of the drain cover should be level or close to level, yes. But not if it means that the pipe is now level.... The pipe has to drain water, with a slight slope, of 1/8th" to 1/4" per foot. That is important. More important than the level-ness of the drain cover. Is the length of pipe long or short? After the P trap, does water travel a long ways until the next connection, or a short ways?

david

[djohnson]

It is probably 4 feet from the trap to the next connection. That's a good point about the slope to the connection.

Sounds like I should figure out what the height of the pipe coming out of the trap should be relative to the next connection and then brace the pipe so that it has less/no play. Then, I can put down the subfloor with a hole just big enough for the drain and won't need to hold the pipe underneath (as commented above). Is that right?

[geniescience]

support 2" diameter pvc pipe right under the drain or closeby? Sounds right to me.

david