Tapping into existing vent

Users who are viewing this thread

Jefftra

Member
Messages
30
Reaction score
3
Points
8
Location
Missouri
Can anyone suggest the proper way to splice into this vent? I need to run vent from new bathroom in basement to this location. The pipe going up the floor is the existing vent. I’m afraid if I mess this up I can’t really redo and don’t want to be tearing walls out above. Thanks. 8932F110-A051-4C5D-99FF-B9A21FC2BA5E.jpegC026BF7F-EBC1-4085-AFCB-2BF0E675EDD0.jpeg
 

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
The basic answer is you can't tie your basement bathroom vent in there.

That 1-1/2" pipe segment is a vent for the two fixtures on the floor above coming in at the two san-tees (bathtub and shower?). So that vent can't combine with any other vent lower than 6" above the flood rim of those fixtures. You'd need to run your new vent alongside and parallel to that vent, then in the story above when you are high enough, you can combine your two vents.

Or, since you said in your other thread that you are under the IPC, you could consider an AAV for venting the basement bathroom.

Cheers, Wayne
 

Jefftra

Member
Messages
30
Reaction score
3
Points
8
Location
Missouri
The basic answer is you can't tie your basement bathroom vent in there.

That 1-1/2" pipe segment is a vent for the two fixtures on the floor above coming in at the two san-tees (bathtub and shower?). So that vent can't combine with any other vent lower than 6" above the flood rim of those fixtures. You'd need to run your new vent alongside and parallel to that vent, then in the story above when you are high enough, you can combine your two vents.

Or, since you said in your other thread that you are under the IPC, you could consider an AAV for venting the basement bathroom.

Cheers, Wayne
Oh wow glad I asked this question. Im not sure how they expect a home owner to run a vent pipe from the basement to the attic without tearing out drywall above. I'd rather not have to use the aav but not sure any choices.
 

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
I think you mentioned in the other thread that the builder roughed in the basement drains? So if the builder didn't rough in a vent in the ceiling, then they took the easy route of expecting you to use an AAV (since you are under the IPC and that is allowed).

But I thought in the other thread you mentioned some work you're doing on those drains above. Opening up the drywall on that wall isn't a part of that job?

Cheers, Wayne
 

Jefftra

Member
Messages
30
Reaction score
3
Points
8
Location
Missouri
I think you mentioned in the other thread that the builder roughed in the basement drains? So if the builder didn't rough in a vent in the ceiling, then they took the easy route of expecting you to use an AAV (since you are under the IPC and that is allowed).

But I thought in the other thread you mentioned some work you're doing on those drains above. Opening up the drywall on that wall isn't a part of that job?

Cheers, Wayne
Yea they took the easy way out. I talked to my inspector and they won’t allow me to do the AAV since a toilet is involved. I now have to tear out drywall in the master bedroom to access that vent pipe. Wife is not to happy.
 

Tuttles Revenge

In the Trades
Messages
4,132
Reaction score
1,410
Points
113
Planning ahead is hard sometimes. Plans review wants to have permits for all Planned Ahead fixtures even if you're just stubbing a pipe for Maybe.. we've hit that road block a couple times.. usually we just do it after inspection.. but its still a pain.

The wife will be unhappy temporarily til the new bathroom is finished and then she will be happy longer.

Some things in the code are kind dumb and have zero real purpose.. But this code actually has a good reason for being there. In cases when drains get clogged and you don't realize it.. eventually the waste will come out in a nearby fixture or in the fixture you're using. However, if you tie in another fixtures drain below the flood level of the fixture that has the clog, the waste water will reach the combined vent and simply follow that path.. and you may never know you have a clogged drain until it becomes Really bad... I lived in a house with the worst plumbing ever and it had that exact circumstance..
 

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
I talked to my inspector and they won’t allow me to do the AAV since a toilet is involved.
I suggest getting a hold of a copy of the plumbing code in force in your area, up.codes doesn't cover Missouri, saying that it varies by municipality. If it is based on the IPC, then they would have had to explicitly amend section IPC 918 to cover what the inspector is saying. If they haven't amended that section, then the inspector can't impose that requirement, and you should be able to use an AAV.

Here's the unamended version, FWIW. There are no exclusions for WCs.

https://up.codes/viewer/colorado/ipc-2018/chapter/9/vents#918

Cheers, Wayne

P.S. If their really is a local amendment, then the builder should have known that and provided a rough-in vent. So if you are within your builder warranty, you could go after the builder.
 

Jefftra

Member
Messages
30
Reaction score
3
Points
8
Location
Missouri
I suggest getting a hold of a copy of the plumbing code in force in your area, up.codes doesn't cover Missouri, saying that it varies by municipality. If it is based on the IPC, then they would have had to explicitly amend section IPC 918 to cover what the inspector is saying. If they haven't amended that section, then the inspector can't impose that requirement, and you should be able to use an AAV.

Here's the unamended version, FWIW. There are no exclusions for WCs.

https://up.codes/viewer/colorado/ipc-2018/chapter/9/vents#918

Cheers, Wayne

P.S. If their really is a local amendment, then the builder should have known that and provided a rough-in vent. So if you are within your builder warranty, you could go after the builder.
Yea he specifically told me he wouldn’t allow it, but I want to do it the best way so here we go. Just to make sure I need to be how many inches above the lowest drain on the first floor.? I assume go 4 inches above the p trap in the sink. Also when I tie into that existing vent would I just use a regular t or a santee? And ok to use 1.5 for the vent or do I need 2 inch. Thank you!!
 
Last edited:

wwhitney

In the Trades
Messages
6,532
Reaction score
1,822
Points
113
Location
Berkeley, CA
Yea he specifically told me he wouldn’t allow it
My point is that it's not up to the inspector to allow or disallow, what matters is the written code adopted by your jurisdiction. So that's why I'm suggesting checking what the written code says about AAVs. The inspector should be saying "IPC 918.blah disallows it" where 918.blah is a local amendment, not "I won't allow it."

When two vents join, it needs to be at an elevation at least 6" above the flood rim of any of the fixtures being vented. So above the p-trap is not enough, if it's the highest fixture involved is a sink in a 36" high counter, it would need to be at least 42" above the floor. You can join vents with any 3 opening fitting you like, wye, san-tee, vent tee, combo (unusual), etc.

Cheers, Wayne
 

Jefftra

Member
Messages
30
Reaction score
3
Points
8
Location
Missouri
My point is that it's not up to the inspector to allow or disallow, what matters is the written code adopted by your jurisdiction. So that's why I'm suggesting checking what the written code says about AAVs. The inspector should be saying "IPC 918.blah disallows it" where 918.blah is a local amendment, not "I won't allow it."

When two vents join, it needs to be at an elevation at least 6" above the flood rim of any of the fixtures being vented. So above the p-trap is not enough, if it's the highest fixture involved is a sink in a 36" high counter, it would need to be at least 42" above the floor. You can join vents with any 3 opening fitting you like, wye, san-tee, vent tee, combo (unusual), etc.

Cheers, Wayne
Well I think I lucked out. I was about to start cutting drywall out when I realized the vent pipe I was going to tie into was actually behind the shower wall. I went to the attic and saw where all the venting came together. I found this pipe in the basement close to the bathroom rough in above the duct work. Is there a way to prove this is for vent? I am thinking that has to be for venting.

E57B502F-78C9-4306-B365-3C3FD1B9B4C7.jpeg53252E37-4442-440F-99FA-361316345C12.jpeg
 
Last edited:

Tuttles Revenge

In the Trades
Messages
4,132
Reaction score
1,410
Points
113
If the pipe in the basement ceiling is open.. you should be able to hear plumbing being used by listening at that open pipe and flushing a toilet. If you can hear it, its connected to the drain and vent system. Technically it could be a drain, but you would have to make a guess based on the probability of it being a drain. Its relatively new construction, so not likely to have been leftover from a remodel.

If the pipe is capped.. expect there to be a bit of water from condensation in there.
 

Jeff H Young

In the Trades
Messages
8,766
Reaction score
2,168
Points
113
Location
92346
jeffra 905.6 requires a vent to be roughed in when roughing in a drainage system so where was inspector when contractor built this. I saw that several days ago and just though of it. if this place is pretty new I think its fair to expect builder to bring a vent into basement and handle the patch and paint above. cheap skates should provide vent and code enforces they do it. relying on AAV is hack work no excuse for them to have left it out
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks