DWV (venting) question

[Stephenson]

Getting ready to close in bathroom remodel, after having moved all the fixtures.

Bathroom is on second floor and was previously serviced by a stack with several vent connections supporting the this bathroom and several fixtures downstairs connected into the vent stack in thus bathroom.

Due to space constraints we decided to use AAVs under cabinet (it's allowed here) for the two vanity sinks. This leaves three other vents into the attic space (one servicing the newly moved toilet/shower, and two from downstairs fixtures) that we were going to use AAVs on, as well

Since there is an existing through the roof stack still hanging (temp capped in the attic ...and full of water since stack connection to drain was removed - we were going to remove it and re shingle), could I vent the three lines with a covered stack of some sort?

There is also another vent stack through the roof servicing bathrooms on the front of the house - we're on septic system - will this other vent tank fumes sufficiently?

 

[hj]

quote; with a covered stack of some sort?

What do you mean by "covered stack"? Do you mean put a sealed cap on it? If so the answer is a definite no.

 

[Sponsor]

 

[Stephenson]

Hi HJ ... No, meant a rain cover to prevent water from getting into the pipe ...since it would not drain back properly, keeping water out while allowing vertical vent would be better than AAV ...and still allow gases to escape?

 

[Terry]

since it would not drain back properly,

If the vent does not drain, then it's no longer working as a vent.
A vent pipe is an empty pipe, that is installed in such a way that any rainfall drains down the pipes to the very end. If the pipe is filling with water, it must have been changed.

 

[Cacher_Chick]

All vents must be installed so that they drain, regardless of whether it is using an AAV or a atmospheric vent.

 

[Stephenson]

In my circumstance, the stack came from through the roof with several fixtures venting into it in the attic, thence through the second floor bathroom to under the floor where it connected into a 4" drain which serviced the bathroom fixtures. It turned down to the first floor somewhere out of site.

As it looks now, the shower and toilet line vents straight up into attic (I have temporarily capped it), two lines from the first floor come together and vent up into the attic with an AAV, and another separate vent enters the attic within a few feet from somewhere downstairs (is still connected to what remains of the original stack). Since the toilet/shower vent comes straight up off the drain which connects to the main drain, can I connect it through the roof and use it as a stack for the other two vents, taking it through the roof? Is this better than using AAVs on all of them?

 

[Stephenson]

Here's what remnant of stack look like in attic. Bottom is capped just above ceiling ...yeah, some water in it too!

 

[Stephenson]

Here's the three into one venting from below the second floor bathroom.

 

[Stephenson]

And a poor photo of the toilet, vent and shower ...

 

[Terry]

The preferred method is always venting though the roof.
Combining vents above the flood level is fine (42" in most cases)

 

[Stephenson]

Forgot to explain ...the carpet padding was my way of trying to deaden flushing and draining noises.

 

[Stephenson]

So, to restate my question, should I run the vent that runs from the top of the shower/toilet drain line to the roof and connect the 3 into 1 and the other vent from downstairs INTO it - using it as the stack since I know it runs directly into a drain? This would be better than three separate AAVs?

 

[Cacher_Chick]

If i am understanding what you have there, The "dead end" section of vertical stack needs to be disconnected or removed from the system. The vent through the roof must not have any arrangement of piping that would allow it to hold water.

You can tie other fixture vents into the section going through the roof. All piping must be pitched to gravity drain. A real vent is always better than an AAV, because an AAV is a mechanical device that is guaranteed to fail eventually.

 

[Stephenson]

Thanks, cacher-chick ... Of the lines I could use as the "main" vent (the one I attach the others to), which one would be best? It seemed like the one I know goes to the top of the drain line near toilet would be (cause I can see it is run off the top of the drain) ...is this correct assumption under this circumstance?

They are all 2" ...should I transition from 2" to 3" on this line in the attic and then connect the other 2" vents to it (straight or sanitary T?) and then through the roof - or stay 2" all the way thought the roof? Rain water would drain down past the 2" sanitary Ts, and into the 2" section and then out through the toilet drain ...am I understanding this right?

 

[Cacher_Chick]

So that there is no misunderstanding, it might be best for you to draw a picture showing the vent stack with the layout and fittings you think will be appropriate and post it here for review.

 

[Stephenson]

Sorry this is such a bad drawing ... busy day at work and like everyone, trying to juggle! Tried .pdf but file size too large ... took photo of my very very rough drawing ...thank you for your help!

 

[hj]

quote; a poor photo of the toilet, vent and shower ..

Actually, it is a photo of a "poor" toilet and shower piping, regardless of the vents, or lack thereof.

 

[Plumbpro]

A rain cap on a vent will not prevent the vent from filling with water if it has no place to drain. Water vapor from normal use of your plumbing will eventually fill the pipe full of water and render the vent useless. From your picture though it looks as if every thing does connect to a drain. Do the pipes that go down stairs connect into any drains or are they capped off?

 

[Stephenson]

Yeah, HJ, I agree ...it isn't my work ...and, frankly is the reason I like to do as much as possible, myself ...if it can learn from folks like you, I can either do it myself or make sure someone else does it right.

Plumbpro ...everything going down services either the adjoining bathroom on the second floor (has shower, toilet and sink), a 1/2 bathroom on the first floor, and/or a bathroom on the basement floor - there is another vent stack on the other side of the house, so can't really tell with total certainty. All fixtures are in daily operation.

 

[Stephenson]

HJ, is there anything you believe that won't work adequately? I now realize the plumbing isn't the way it should be ...but, what can I do now, short of tearing the floors, shower, etc up and starting over?

Given the vent piping, what is best course of action at this point - which of the available three lines going into the attic should I use as the "stack" to connect the other two in to?

Thanks and Happy Thanksgiving!