Trim horizontal pvc drain line height?

[bdey01]

I have recently begun to remodel a storage space and 1/2 bath into a full bath. The storage space comes from my garage, which was 6" below the existing living space height. Drain lines to connect with existing septic tank drains were run via cutting channels in the storage area floor and the pouring concrete to make new floor continuous with existing living space. However, the shower were were creating is a true no-curb walk in with the floor already 1.5" lower so as to use a pre-sloped shower pan with a linear drain on one end. The issue is that in order to connect to the existing drain lines and maintain proper slope for drainage, the height of the shower trap and trunk line to vent and further drainage was basically right at the height of the lowered concrete section for the shower. It ended up being about 1/2" above the height of the floor, because of some connection issues further down the line that couldn't be avoided.

So now I have a 2 foot length of pvc that is protruding in basically the center of the shower about 1/2", and then sloping down to flush with floor at the edge of the shower wall. This will be covered by the pre-sloped shower pan, but only if I carve out a hemispherical length of foam from the bottom of the pan to fit over this protrusion.

My question is: in order to minimize the amount of foam I have to remove from the bottom of the pan (and not worry about cutting through the top of the pan), can I use a grinder or sander and mill off the top of the shower trap drain pipe hub which adds about 3/16" of height over and above the 1/2" of the pipe run itself? And if so, can I use additional pvc cement or epoxy or whatever to seal this sliced area and seal it against leaks later on?

I know that this whole thing is not ideal, but I cannot fix the pipes and still get slope for drainage, so I am stuck with the pipe protruding slightly. Since it is not pressurized, and the top is the only part protruding, my hope is that glue or whatever will keep any water that might collect up to that height during shower usage still inside the pipe, and I can use this pan effectively. What do you guys think?

 

[hj]

I really do not understand completely what you want to do, but on the surface it appears to be a VERY BAD idea. Pipe glue will NOT seal a hole in the pipe.

 

[Sponsor]

 

[bdey01]

I wasn't going to cut a hole in the pipe, but just plane off part of the exposed section of the hub flange so that the overall height will allow it to be put under the shower pan such that the top plane of the shower pan isn't compromised. Otherwise, the exposed flange is too tall and will cut through the top plane of the shower pan and ruin its waterproofability(?).

 

[Reach4]

I suggest you post a photo. Either post a link to a photo, or upload a picture 800 pixels and 200 KB or less.

 

[Terry]

Please don't do that.
Shaving a pipe to a paper thickness is not good.
I would rather see you raise the pan. Small piles of mortar mix help to do that.

 

[Jadnashua]

It sort of sounds like you're using something like either the Kerdi system or maybe Wedi. Those only work if they are properly bonded to the substrate. Sitting over a pipe is probably not a great idea as that can flex, and tile does NOT like flex!

 

[bdey01]

I took some photos. The first image shows the larger area of the shower floor where the presloped pan will go. It is about 1.5" below the height of the surrounding concerte floor. You can see that over toward the right, the pipe is sloping down and falls under the height of the pan, but gradually creeps up in height toward the middle and the underside of the foam of the pan will need to be carved out to make a pocket for the pipe. The red line on the second image shows the height I need the pipe hub at, roughly just under 0.5". It looks like the hub will be trimmed down, but not completely removed.

The pan I am using is from Laticrete, a Hydroban Pre Sloped linear shower pan. It has a slot in the end, where the large vertical pipe is shown on the first image, where a linear shower drain goes. My plan is to not compromise the top Hydroban coating, and to cover the pipe with a layer of thinset, and line the inside of the carved out part of the pan with thinset as well.

 

[Asktom]

Raise the floor. Don't whack off the pipe.