Linear drain install mishap

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branimal

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Feb 27, 2017
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I installed a schluter Kerdi linear drain a couple of days ago and I have a problem.

My drainage riser and trap are 2” pvc. I have no access to the plumbing from below so I have to mortar the linear drain to the subfloor and glue the riser below and the stub connected to the linear drain in one shot.


I attached the stub of pvc to the linear drain with the appropriate coupling. To calculate the stub length, I measured the distance between the top of the subfloor and the stop in the coupling attached to the riser. From that number I subtracted the length of the drain outlet on the linear drain sticking into the drain whole and added 1/8” for mortar.

This number should be my pvc stub length.

I attached the drain as described above and held the drain down for 30 seconds to make sure the pvc firmly bonds. I did feel the pvc pushback against my downward pressure but I held it down and I thought it connected fine. I have 3 pipe clamps holding the trap in place so it really cannot move down on me.

After I installed my linear shower tray, I noticed the drain was sticking up near the drain outlet. It’s sticking up about 3/8”. I think The Stub length of pvc pipe is too long or something else went wrong.

I’m going to use an internal pvc cutter to remove the linear drain and try this again. But I want to know what went wrong.

Here are my guesses of where I messed up:

1. 1/8” thick mortar was over estimated.
2. The pvc pushed back when gluing and created additional length causing the drain to not sit flush.
When gluing pvc, it should be held down longer than 30 seconds. I’ve heard it moves even after 1 minute.
3. I over calculated something else

Any thoughts on where I went wrong?

When gluing 2” pvc pipe to a coupling do I need to get the pipe the entire 3/4” way into the coupling? Is there a margin of error here. That could help me make sure I don’t mess up again.

I’ve attached some pics so people know what I’m talking about when referring to a linear drain.

878d825f1fe66d1165404a6c3f8f14e3.jpg

6b2f83a42340fe65dff97e1b39244304.jpg
 
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