Question for Plumbers....

[mooseburger]

i am doing a bathroom reno....( bath tub to Walk in shower ) on a concrete floor, tub is already out and recycled. existing drain is 1 1/2 ", I removed existing P trap also 1 1/2".
Question is: do I increase to a 2" P trap ( I assume that it would be for venting ) also the drain is roughly 18 to 20' away from the main drain, through a finished ( carpeted ) bedroom, which I do not want to disturb.
Thanks for all and any help, and for taking time to read and respond to my post. MB

[Bigdad013]

Do not eliminate the P trap. It is in place to hold a small amount of water in the drain pipe. That small amount of water keeps sewer gas from flowing into your home. Does the new shower have a 2" drain on it? If it does, you could put a reducer on it to 1 1/2". Unless your having it inspected, stick with the 1 1/2".

[ksteed17]

By code you can have an 1 1/2" shower drain although most come 2" and I usually always run mine 2" but without jacking the floor your stuck with what you have. Your shower will most likely be wet vented through the lav in the bathroom on an 1 1/2" line you have 6' till you need to be vented. If I saw your layout I could say pretty close how they piped it. Either way you'll be fine.

[Stu]

How many shower heads are you putting in your walk in shower?

[CaberTosser]

The 11/2" is sufficient unless you plan on relocating it a great distance, as there are distance limits from the vent based on pipe size (8' for 2" and 6' for 11/2"). The pipe should not have a drop that exceeds it's diameter before reaching a vented line is the basic premise.