Shower P Trap in Ceiling

[1969SSCamaro]

Doing master shower refurb and finally ready to connect P Trap. I had to relocate the shower drain a few inches to the other side of the Joist. See photos. I thought this would be easy, but now wondering if this can be done per CA code given the tight space? I understand that I should not use the San Tee I was planning to use and should use a Y? 1st photo shows location of exterior wall. 2nd Photo shows approximate old drain location (left) and new drain location. 3rd photo shows better view of old drain location (note where joist was chiseled to accommodate old drain location). last photo shows new parts I was originally planning to use. One problem I have is clearance between sheetrock and centerline of waste line is 5.5". The old Y (now capped) was slightly angled up because of this (I think). Anyway, what is the best approach and was the original configuration code compliant? Any help would be greatly appreciated. Thanks,

 

[phishfood]

Don't use the santee, use a wye.

I don't know Cali code, but under IPC, you can use an 1 1/2" trap with a standard shower, as long as the GPM of the shower valve and head fall within the allowable limit for 1 1/2" trap. That would gain you a little bit of height.

 

[1969SSCamaro]

Thanks Phishfood, but I'm guessing the 12.5 GPM valve and three showerheads would be too much water? The only approach I've been able to come up with stinks; see attached photo. I'm guessing this is beyond stupid and is also like an S Trap. I'll go back to the Y and see what I can figure out.

 

[1969SSCamaro]

Okay, I think I finally pulled my head out and have a good solution using existing Y and drilling new hole for P Trap Arm (I was trying to avoid drilling more holes and weakening joist above shower floor). See attached photo. Only potential issue is slope from P Trap to the Y might be a little steep; maybe 1" for a 16" run. Does this look like the best way to go? Any potential code issues? I should be within 5' of vent. Or, is the previous approach acceptable?

 

[Mr_David]

extend the pipe from the wye a bit more to give a little more wiggle room on drain tail pc.

If that is the vent. Horizontal vent has to be above the flood rim of the fixture.

 

[1969SSCamaro]

Thanks Mr David, that sounds like a good idea to extend from the wye. What you see is all the original plumbing (1986). On the left side is an exterior wall (maybe 12") and the side the waste line is sloping towards. I assume to the right is the vent; maybe vents the adjacent bathroom as well. Or would it make more sense if that were a waste line from the adjacent bathroom. I'm off to the orange box for 2-1/2" hole saw.

 

[phishfood]

Thanks Phishfood, but I'm guessing the 12.5 GPM valve and three showerheads would be too much water? The only approach I've been able to come up with stinks; see attached photo. I'm guessing this is beyond stupid and is also like an S Trap. I'll go back to the Y and see what I can figure out.

If you truly are flowing all 12 1/2 GPM out of your showerheads, than you are just over the allowable limit for a 2" trap, per 2010 IPC.

The important thing to remember is that the top of the pipe at the wye needs to be higher than the bottom of the pipe at the P trap. That way, so the theory goes, the pipe will never fill up with water to the point that no air can get back to the P trap.