Vent pipe through lower roof

House with 2 bathrooms, one up/one down (both baths in corners you can see). There was no plumbing vent through upper roof, and only one was the one pictured in lower roof. Technically, vent pipe is above all fixtures in upper bath.

Any reason for concern or would you comment on?



Probably an AAV in the attic. If you can’t find it allow a Certified Plumber to find it.

I looked and did not see any other means of venting.

So if the upper bathroom main drain runs through the lower attic into the pictured cast iron stack/vent, this wouldn’t be acceptable due to the distance away from the fixtures, correct?

O.k. let me rephrase my post a tad, cause I’m having difficulty sorting through all the responses :).

If this was at a property you inspected, what would you say in your report regarding plumbing vent?

So you are saying that the upper floor is venting through the lower floor vent stack on the roof? I am not sure how it could be. I would call for further evaluation on this. How did the tub or shower drain under a load of water?? I will fill a sink and bath tub up and drain them at the same time just to see how they work together. If they drain slow or bubble and suck then I call them up for evaluation.

Yes, or at least appeared that way.

Everything drained fine and/or normal

This was what I did.

OK smart a-s-s lol
So is the top of that PVC vent above the bathroom fixtures and how far distant to the lower roof vent as there is a limit as to how far you can go horizontally.

A couple well placed arrows like I hope you do in a report would help.

[quote=“belliott, post:9, topic:72357”]

and how far distant to the lower roof vent


Quite a ways away (the whole lower roof).

[quote=“belliott, post:9, topic:72357”]

as there is a limit as to how far you can go horizontally.


What is that limit?

Oh now you want me to work for you ,OK was hoping not to need looking this up.
First gotta be at least 10 feet from that window…check.

On the bright side, once you let me know, I’ll be a smarter ***:smiley:

905.1 All vent and branch vent pipes shall be free from drops and sags, and each such vent
shall be level or shall be so graded as to drip back by gravity to the drainage pipe it serves.
The vent pipe cannot have a drop or a sag.
The horizontal vent pipe can be installed level and does not need a fall or 1/4 inch per foot.
When you install a horizontal vent pipe with 1/4 inch fall, the slope shall be graded so the
water flows into the drain pipe.

905.3 Unless prohibited by structural conditions, each vent shall rise vertically
to a point not less than 6 inches above the flood-level rim of the fixture served
before offsetting horizontally, and whenever two or more vent pipes converge,
each such vent pipe shall rise to a point at least 6 inches in height above the
flood-level rim of the plumbing fixture it serves before being connected to any
other vent. Vents less than 6 inches above the flood-level rim of the fixture shall
be installed with an approved drainage fittings, material, and grade to the drain.

See 31-2

Call it out as no adequate venting noted for the second story plumbing and recommend evaluation and repairs by a licensed plumbing contractor.