Roughing in PVC shower drain through slab


Old 08-06-13, 02:59 PM
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Roughing in PVC shower drain through slab


I am getting ready rough in a new shower drain through the slab on my bathroom. I have whole in the concrete cut, the old P-Trap cut out and and my PVC 2" pipe ready to go. I will be making my connection to the original ABS plastic with a 2" Stainless/Rubber mechanical sleeve connector. I was told by my plumbing supplier that this was the way to go for joining PVC/ABS waste water connections. I have a plywood template made up for assuring proper alignment of the 2" drain with my shower pan.

Before I start I have some questions.

1. After all is connected, and I have back filled, covered the hole with plastic etc.. I will pour cement to cover the hole. I assume I need wiggle room to connect the pan. What works best a short piece of 4" PVC with cement poured around it?

2. How much of the 2" PVC should I leave sticking out of the hole. I'm guessing 3'-4" and then trim it back later as required?

3. I assume when I put mortar down to secure the pan that I can just put some inside the PVC casing.

My first time doing this. I pretty handy but figured I ought to ask someone who has done this before. I don't want to make a mistake and literally have it set in stone..
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Old 08-06-13, 03:37 PM
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What type of drain do you have, compression or solvent weld?

If compression, I would plan on a couple of test fits. One with the pipe cut long, dry fit and tack the base in place, put on the compression ring and then mark where the excess pipe needs to be trimmed.

I don't think that you need to do anything other than back fill the hole with dirt unless the hole extends outside the base area. I would want your pipe to have the ability to flex a little. The drain and base are going to react differently differently depending on if a 100 lb woman is using the shower or a 300 lb man I would allow for slight movement of the drain assembly. This will also allow movement for expansion and contraction from the hot water.
Old 08-06-13, 04:42 PM
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I only just purchased the pan today and have not purchased the drain yet so I could go either way. I bought the Moen/Sterling 60 x 30 Acrylic pan. It did not come with a drain. I'm thinking the compression drain fitting is way to go right?

I had to make a pretty good size hole in the concrete and I bought a bag of Quickrete to cover back up and actually exposed a couple tension cables in the foundation so I thought it a good idea to re-concrete over them. In allowing for a little movement of the drain that was where the idea came in about the PVC casing. 4" pipe should allow for an inch or so of movement in either direction. I could squeeze some silicone onto the hole to seal it. I have had subterranean termites here before and I'd kind of like to keep them out.

But anyway I think I get it now. Purchase the drain assembly and trim the pipe to fit.

Thanks for the reply.
Old 08-06-13, 06:12 PM
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I'm thinking the compression drain fitting is way to go right?
yes the only way IMO on a slab...

If your doing mortar support and all lines up on the dry fit... yes I would seal the hole...

Movement or expansion should not be an issue IMO...
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