Our tub/shower unit is on a concrete slab. I want to install a tile shower with center drain. Upon removal of tub and digging out of sand below tub drain I do not see a p trap. Our center drain will be located about 31 inches from existing drain. I removed concrete and created a channel from existing drain to new tile shower drain location. Should I install p trap below shower. I have enough room now that I have removed the concrete and sand. . How do I know there is not a p trap already installed down the line somewhere that I cannot see.
Would this new trap cause a problem if there is already one installed somewhere.
Never had smell from old shower/tub unit and there is a stack that runs up in the wall right near our old tub. It goes into concrete and I can assume it is attached to this waste line buried below concrete level.

Quick response appreciated as the weekend is here. Thanks

It is highly unlikely that you do NOT have a "P" trap, but if not you do need one. However, if you install one and there is already one under the floor, the shower will NOT drain properly, if at all.

How can I find out for sure. Would the smell be really bad. We live in gated community where homes were all built in 2000. Is smell the best indicator. As we have never had that. Just thought odd not seeing p trap right below old tub.

you either keep digging around to see where that pipe goes or have someone send a sewer camera down the open pipe.

I will try digging a bit more tonight. Unfortunately it is below slab and I only have small opening where the sand keeps filling in when I dig?. Is it safe to say if I never had issues with tub the way it is configured that I won't have issues with shower configured the way it is.
Never any odor. Thanks

when you venture into the unknown, no statement you make can be a safe bet.
the last thing you want is to get the shower in and finished then find out there is a problem.
i'm not gonna tell you to go ahead. but, it is your house and if you want to take a chance... well, extend the pipe over to where it will be located, run water from a hose down it to make sure it drain, leave it for a few days to see if you get any smell and from there you are on your own..

Appreciate your input and advice.. Did spend about 1 hour digging tonight. Had to break out some additional concrete but I did find that p trap. Think I can move forward with out worry.
Thank you. Joe



Edited 1 times.

Joe, the trap needs to be directly below the shower drain, so the existing one would need to be moved.

Correct, it's not right just to leave the trap where it is and have a horizontal pipe run from it over to the new drain.

Sorry if I'm tossing a fly into your ointment, but the trap arm on a tub is usually 1½" and a shower should have a 2" drain. The overflow (your bathroom) is a lot lower.