Hi guys, I'm back with another new adventure! We moved back to Long Island NY and are now proud owners of a great little 3-bedroom 2-story colonial that was built in 1916! Knob and tube, lath and plaster, the whole works!

Now for the plumbing issues: House has a full bath upstairs, and at some point a half bath was added downstairs. I am planning to reconfigure the downstairs space to add a shower, making the half bath a full bath, so we will have facilities to use while I remodel the upstairs bath.

Here's a photo of the back of the house, the 1/2 bath lives in the small addition on the back, while the full bath is is the middle window on the 2nd floor. If you look close you can see the vent stack on the roof.





So you can see from the pics that there is no access to the main vent stack from the 1/2 bath area.

Here is what the drain situation looks like:







We have city sewers here, so where the waste line exits through the wall, it runs to the street and connects to the sewer line. You can also see the vent going to through the foundation wall to outside.

The 2" PVC line that ties into the main CI line is from the kitchen sink. That was vented through the wall like this:



I closed that up and added a studor vent under the sink.

The 3" PVC is what comes from the half bath toilet and sink. It looks like he tied into what was supposed to be a cleanout, and then added another trap? The issue is that the toilet isn't vented and it flushes like crap. The sink, however is vented:



So the new configuration will have sink, shower, toilet. The question is this main connection correct, or should I eliminate the second trap and tie into the main line? Also, can I add a soil stack through the roof of the addition? Are there codes because of the 2nd story windows?

Not getting this inspected but at the same time I want it to be correct and compliant.

Re-Modeling homes for 35 years.
I am NOT a licensed plumber.

looks like the running trap in the basement that serves the new toilet is not vented like the old cast iron one is. that is probably why the toilet doesn't flush well.
as for the vent thru the addition roof, my code calls for it to be 10 feet away from an opening window.
how is the pvc tied into the old cleanout?

You could run the vent up between the windows and thru the roof. Keep it back next to the siding and paint it the same color.

Can I just connect to where this cleanout is and run a vent through the foundation like the CI side?

No, the vent would need to be on the toilet side of the trap.

Good point, but same question though. If I tee into the 3" PVC on the toilet side of the trap, can I just run a vent through the foundation like on the CI side in the pic?

You 'could' but the CI vent is actually a fresh air INLET vent. Very 'old school' as the original plumbing had NO wet vents.

Hold up a piece of tissue and you may see the air flow.

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Wow I know less about this than I thought! Venting has to be the most confusing part of DWV, unless that's just me because I'm not a plumber.

So, what's an acceptable way to address this? Is there another option to running a stack up through the roof of the addition, along the house and up through the 2fl soffit? Can I use an AAV?

In most cases you could use an AAV, but not in your case, due to the house trap. You need to be able to relieve positive pressure from the drain system and an AAV will not do that.

Can I eliminate that house trap since the fixtures will have traps?

According to the 2015 NY State Plumbing Code(2015 ICC), unless you have a local amendment, you don't need it.

Yes , you can eliminate the house trap, use individual traps at the fixtures and use AAV's.

Ok thanks for the info guys!



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