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View Full Version : Tub/Shower Drain/Piping Question - ABS DWV fittings


Andy_D
Jul 10, 2013, 10:38 AM
Hello,

I am in the process of renovating a bathroom necessitated by a crack in my old FG Bath/shower unit. I have bee wanting to replace the bathtub with a shower.

It is my understanding that 2" piping is required by code for a shower. The bath was plumbed with 1-1/2 as standard(almost seems like it might have been 1-1/4" on the metal part of the drain.

If you look at the picture attached there is 1-1/2" abs pipe going into the P-Trap. The P-Trap itself appears to be a 2" based upon specs for 2" ABS DWV fittings (O.D 2.38"). However it also appears that the P-trap is 1-1/2" on the house side and 2" on the outboard side. You can see in the picture that the union to the 1-1/2" pipe has a thick wall to it, and feeling in the hole I can detect a much thinner union wall.

Question: do they make reducing P-Traps? I suspect I have 2" lines at the P-trap and 1-1/2" above. I want to install a shower AND I want to be in compliance with code. I need to get some things cleared up before proceeding, and chipping out concrete and breaking apart drainage piping.

Andy_D
Jul 10, 2013, 11:01 AM
Picture I forgot to attach

https://dl.dropboxusercontent.com/u/12183322/CIMG1375.JPG

Andy_D
Jul 10, 2013, 11:20 AM
With a little more inspection I suspect that I am looking at a 2" P-trap with a 2" x 1-1/2" Bushing reducer glued into it.. I believe I can feel it with my fingernal.

So I'm guessing I need to remove enough concrete to reveal the drain pipe, cut inset a union and a new P-Trap and go 2" all the way?

massplumber2008
Jul 10, 2013, 02:03 PM
Hi Andy

Yup! Looks something like what you propose. As you said, remove enough concrete to reveal the drain pipe, cut the pipe and install a coupling and a new 2" P-Trap directly under the new shower strainer.

Good luck!

Mark

Andy_D
Jul 10, 2013, 03:05 PM
I'm guessing that I should have the new shower pan here before I do anything in order to make sure I have proper alignment with the drain before back filling the foundation with new concrete.