Is it better to have the 12 to 14 in riser before or after the p- trap?

What raiser are you referring to? If it's a vent it comes after the "P" trap. Does this answer your question? Tom

Riser, meaning the distance in elevation between the shower drain and the line I will be T'ing the drain into. Does/will it make a difference if the p- trap is closer to the Shower drain or closer to the T? (up high or down low).

Does that make sense? Maybe I am not explaining it well enough, it might just be my OCD that can't make the decission.

Thanks for your help!

Hold the phone! Are you saying the shower drain's lower then the pipe that it's draining into? Elevation has no place in a shower drainage but slope has. Can you be more specific in your explanation? Back to you, Tom

You question and further comments make it unclear as to what you are trying to achieve. Water only flows downhill unless pumped. The drain and piping must be below the floor and drain down into a drain pipe.

I think I understand what you are trying to accomplish:

Do this:

1. Cut in new Y fitting into existing drain pipe ( has to be after floor drain trap )
2. Run your shower drain pipe towards the shower with 1/4" per foot slope. Here, you will end up at certain height
3. Install 2" trap directly under the shower pan lined up with the drain opening
4. Install "riser" connecting shower pan and trap. Length of this riser is what ever the distance between the trap and pan is. The length of the riser will not inhibit water flow in any way - may it be 2" or 12" long.

Now I have a question: Where are you planning to connect vent for your shower drain ?

Hope that helps. Back to you. Milo

Thanks Guys,Clearly I am confusing everyone.

Yes, water only flows down hill and yes, I am tying into a 2in drain that is vented and that was put in place and never roughed in for a shower drain.

The exsisting drain is currently 18-20in below the subfloor(cement) and only 36in from where the shower drain will be placed. This leaves me with a drastic downward flow in such a short amount of length.

Having the P-trap closer to the floor level(incase in needs to be dug up in the future) means a steaper slope between the trap and the "Y".

Having the trap lower, but still high enough to meet the 1/4in per foot rule between the trap and the "Y", means more riser between the shower drain and the trap.


So... is it or does it make a bit of difference to have the trap higher in the ground and closer to the shower drain, or lower in the ground and closer to the "Y"?

The trap would still be parallel with the shower drain, just either higher or lower.

Can't you see the picture in my head? :)


Waiting patiently... Tag

I got it first time. I think I answered your question in response #6. "More riser" ( low trap ) is your answer. I bet you you will never have the opportunity to "dig out" that trap in the future. Good luck with your project. Milo

Yeah! Mount the trap directly under the shower drain and give it 1/4" slope back to the wye. Now run the raiser up and connect to the showeer \\ drain. Good luck, Tom

Outstanding! Thank you for your wisdom guys.






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