Ask Me Help Desk - Need connection info on building a shower drain.

Hi all and thanks for reading. I'm redoing my bathroom. I want to tile the entire shower including the floor. I've read a lot about how to build a presloped mortar bed and liner. What I don't fully understand is how the drain connection is made. Right now I have plywood on the subfloor and the existing PVC drain is 2". It sits just about an inch lower than the plywood. The original shower had a fiberglass pan and the drain was snugged up against the PVC with a rubber gasket. Never seemed to be a problem with leaks or anything. Now with it removed it seemed kind of wobbly in the hole because the hole was cut much bigger than the PVC. So I basically have 3 questions:

1. Do I need to stiffen the PVC pipe in the hole somehow? If so, how?

2. What do I use to make up the difference between the PVC and subfloor and

3. How is the connection made from the drain on the subfloor to the part of the drain above the mortar bed?

Sorry but I couldn't find any good close up shots here or on the internet of how this would be done.

Greatly appreciate the help.

Thanks.

QUOTE]1. Do i need to stiffen the PVC pipe in the hole somehow? If so, how?
[/QUOTE] Not really! The mortar will keep the drain secure but you can shim the raiser and brace the trap with a 2 X 4 if you're concerned.

Quote:

2. What do i use to make up the difference between the PVC and subfloor

Are you saying that the PVC raiser doesn't extend above the floor line?

Quote:

3. How is the connection made from the drain on the subfloor to the part of the drain above the mortar bed?

This is accomplished by the PVC Flange Type Shower Drain, (see image).
This link may be helpful; Mortar Bed Shower Floor for Tile Showers
Good luck and thank you for rating my answer. Tom

For #2, I need to add another layer of plywood because the current layer is in rough shape. Its not terrible and still sturdy but needs a better/flatter layer on top. Right now the existing riser (not sure I'm using the right term but think that's the section of pipe that comes up out of the hole, duh "rises" up) is just about even with the existing plywood surface (maybe slightly lower). I'm assuming from your question, I'm in trouble..

Quote:

I'm assuming from your question, I'm in trouble..

Perhaps not! The flange type shower drain will set flat against the floor and will extend below it to glue to the raiser. It all dep-ends upon the thickness of the plywood and how much stock is left after you pot it down. If the raiser's still too short it can be extended with a PVC coupling or a shielded coupling,(see image). If you have a poroblem with the raiser click on back and we'll work through it. Don't forget to prime your fittings before gluing them. Let me know if that works for you. Cheers, Tom

Thanks Tom. I'll measure again tonight and see what kind of room there is. Would you know how far down that piece extends from the flange?

Also does the bottom flange piece sit directly on the plywood? Or does that flange sit on top of the membrane with the pre-sloped mortar base under it too? This is where I'm a little confused still.

Hi DIYER:

I remove the strainer and turn the assembly upside down ON CENTER MARK and then I trace around the drain...

Then I use a sawzall to bevel cut the plywood floor so that when I place the drain assembly into the plywood the bottom half of the strainer assembly is FLUSH with the floor AND also well supported by the plywood (see picture).

Then I lay a tar paper down over entire floor area and then I install the membrane... you would then install the TOP HALF of the strainer assembly and cement the membrane in between the top half and the bottom halves of the strainer assembly.

I prime/clean the membrane, the top part of strainer assembly and the underneath part of strainer... any parts that will be cemented. Then I cement all and bolt the strainer together. Be sure to follow instructions set forth by the manufacturer of your membrane, of course!

Be sure not to clog the WEEP HOLES in the strainer as they are essential to keep open. After membrane is all set (dried for 24 hours) you would then do a PAN TEST.

Here, you take some socks and you bundle them into a plastic bag so that you can stuff the bag into the drain, past the strainer assembly, but not so deep that you lose the bag (I would tie a rope onto a corner if go this route) and temporarily clog the drain up tight. Then you will FILL the pan to the threshold level and test the pan for leaks.

I actually use a TEST BALL (sold at all plumbing supply houses... see picture) with an extension on it to clog the drain and then I fill the pan and hold the test for 24 hours. If no leaks, can proceed without worry!

PS... you want to install small pebbles/gravel around the strainer at the weep holes to prevent the weep holes from clogging with cement. Then you would proceed to install mud floor.

Let me know if that all made sense...

MARK

I have to admit you kind of lost me with this explanation although I do appreciate you taking the time. I'm still a bit lost on how this is done and I guess from expert to expert there are probably 100 ways to get it done right. I found this pdf from a Kohler assembly:

http://www.us.kohler.com/onlinecatal.../1090854_2.pdf

Seems to be a fairly good explanation with pictures. If we could get back to my original question: "Also does the bottom flange piece sit directly on the plywood? Or does that flange sit on top of the membrane with the pre-sloped mortar base under it too?"

Seems to me the bottom flange sits directly on the plywood, then you start building up your layers up and around that. Sorry if I'm being thickheaded here but just trying to make sure I do this right fellas...

Still happy to get your feedback please.

Thanks.

Quote:

does the bottom flange piece sit directly on the plywood? Or does that flange sit on top of the membrane with the pre-sloped mortar base under it too? This is where I'm a little confused still.

Half of the flange will set directly on the floor. The other half will bolt down on the shower pan and the mortar will go in around it. Read the instructions I've put up. Cheers, Tom

Thanks Tom. I think I'm starting to get it now.