[lee12]

Getting ready to tie in the drain pipes for a new bathroom into my existing soil stack. Before I cut into it, I wanted to make sure that what I have in mind will be acceptable. Because of the fittings already on the stack, there is not a whole lot of room to add on without dropping kind of low. The following picture shows the existing stack.



Here is what I have planned. The 3" toilet/shower drain comes in from the right (perpendicular to the joists) and the sink drain comes almost straight on (between the joists).



I know that there is currently an S-trap installed for an existing tub (this can be seen in the images). I would really prefer to not mess with what's already in place, but if reworking the whole stack in a way that replaces the s-trap is a good idea, I would certainly consider it. The tub does gurgle loudly when draining - if that's related.

Thanks.

[massplumber2008]

Hi Lee...

Definitely, when you have time, replace the STRAP with a PTRAP and an AAV (mechanical vent)... these traps are famous for sihoning off and allowing sewer gasses into your home. I'm glad to explain and walk through when you are ready to do this, OK?

Otherwise, all looks great just want you to add some cleanouts and use WYE fittings when you connect into the waste stack... see image. You may be able to get away with using only 1 shielded clamp and a coupling for the larger wye connection, but if needed 2 shielded clamps will be fine.

If you are unclear how to cut the wye fitting into the stack... let me know.

Mark

PS: I won't mention the ABS plastic that is connected improperly to the PVC, OK... ;)

[hkstroud]

Mark,
A couple questions if you please.
What is the maximum distance between a 2" trap and the vent.
Is the ABS a vent pipe?

[massplumber2008]

Hi Harold...

In my area, max. distance is 5 feet.

The ABS could be a vent pipe, but it wouldn't be a valid vent for the S-TRAP even if the S-TRAP was replaced with a PTRAP as the vent needs to be above the centerline of the PTRAP... ;)

Why do you ask?

[hkstroud]

For the very reason that you assumed. Assuming that the vent goes straight up, would have thought the tub with a P trap could drain in the top of the 4". Also thought that 1 1/2" was required size for tub drain. What is there now looks like 2" to me, could be wrong of course. Might make a difference in clearance. Going to be difficult to get AAV between pipe and floor
What will vent the lavey?

[massplumber2008]

1.5" in most states, but I did just recently read a code book that required 2" for tubs... go figure.

And yeah, the vent needs to be above the centerline of the tub waste so even if that ABS was a vent it wouldn't fly here.

He'll need to install the new PTRAP and, at a minimum, an AAV vent about 6 inches above the trap.

Thanks!

[lee12]

Thanks everyone for contributing to the discussion here. Mark, thanks for the labeled diagram. I'm definitely indebted to you I'd say!

Regarding the tub drain/S-trap issue, I'll look into this - keeping in mind what you've both mentioned. If there's a solution that can easily be incorporated into the work I'm doing for the new pipes, I'll try to make it happen. If not, I think I'm tempted to leave it for now, just because I have enough on my plate at the moment and it has not presented much of a problem so far. Mark you mention that the main issue with these traps is that they can siphon out and allow sewer gases to enter the house. I have not noticed this since living here so maybe I'll be okay for a little while longer. It is a pretty large, whirlpool type tub that rarely gets used. I'm not sure who did the work installing this bathroom but I'm starting to think it maybe wasn't the best workmanship. It was definitely a remodel done after the original house construction.

Mark - in your diagram you have labeled 'cleanout tees'. I had been picturing cleanouts more as a wye configuration. Any reason to choose one over the other, in general? Just an access issue?

And please, whenever you have the time, I would definitely take you up on your offer to explain 'cutting the wye into the stack'. I see you have 'shielded clamps' labeled, I assume that's part of it.

Thanks again!

[massplumber2008]

Cleanout tees are better than WYE cleanouts as you can only snake ONE WAY with cleanouts on wye fittings... with the flow.

With a cleanout tee (not a sanitary tee fitting and cleanout like in your picture, but a cleanout tee) you can snake in both directions... see cleanout tee below.

I'll post on installing the wye with shielded clamps later tonight or tomorrow, depending n the snow we get, OK?

Mark

[lee12]

That sounds good - thanks. Should I use this type for all of my cleanouts? Is what you showed the same same as a 'test tee'? And related to our earlier discussion about cleanouts on horizontal runs - would I treat this like a test tee (45 degree turn max) or a wye cleanout (90 deg turn max)?

[massplumber2008]

Yes... best to use these "test tees"... ;)

[lee12]

Thanks! Good luck with the weather...

[lee12]

Mark,

Followed what you outlined here for the stack connection, I would guess you intended more or less the same in my case.

https://www.askmehelpdesk.com/go/exp...=1&sort=oldest

I almost finished it up today (the drain part at least... ), I'll post some pictures soon. Other than purple stuff everywhere it looks okay :) Will pressure test this weekend at the latest. Thanks!

[massplumber2008]

Exactly! Appreciate the follow up... ;)