Using Existing Stack and Vent for Basement Sink

[Greg Gunther]

Hello Eveyone,
I am just a DIYer so please excuse my ignorance with terminology. I am pretty handy however so this shouldn't be hard, just need to know if I am doing it right. I have an existing soil stack (yellow text) from an upstairs bath that I would like to use to rough in a new sink (red text) for a wet bar. My questions are:
1. Is this ok to do and any advise on how to do it (fittings, slope, etc)
2. There is an existing dry vent for the basement drain (green line and text). Can I tie into this or should I use an AAV? If I tie into it, any advise on sloping, fittings ext would be great.
Thanks for all your help. See the attached image for details.

 

[Jadnashua]

You can tap into the drain line, a Y is probably your best choice of fitting. Some places will NOT allow use of an AAV, so you may not have a choice. A vent line must go up to at least 42" or 6" above the height of the flood plane of the highest fixture in that room before it can then go horizontal, and any horizontal runs need the same slope as a drain...at least 1/4"/foot. It looks like there is already a banded coupling on that line...that is probably the easiest, code compliant way to insert and attach the new bits, unless you can spread the bits apart to insert a coupling (unlikely). A repair coupling is tougher to utilize, as the cement can make it stick before you get things positioned properly, the banded couplings don't have that problem and are just easier to use.

 

[Sponsor]

 

[Terry]

An AAV would work there, or you can tie into the vent on the other side of the room.
Since that pipe is pretty far below the ceiling, I see no reason why you couldn't go with glued fittings. A vent pulls off at the same level as the trap arm. Venting takes place between the trap and where you would tie into the stack.

 

[Greg Gunther]

An AAV would work there, or you can tie into the vent on the other side of the room.
Since that pipe is pretty far below the ceiling, I see no reason why you couldn't go with glued fittings. A vent pulls off at the same level as the trap arm. Venting takes place between the trap and where you would tie into the stack.

Thanks for the advise. Very much appreciated.

 

[Greg Gunther]

You can tap into the drain line, a Y is probably your best choice of fitting. Some places will NOT allow use of an AAV, so you may not have a choice. A vent line must go up to at least 42" or 6" above the height of the flood plane of the highest fixture in that room before it can then go horizontal, and any horizontal runs need the same slope as a drain...at least 1/4"/foot. It looks like there is already a banded coupling on that line...that is probably the easiest, code compliant way to insert and attach the new bits, unless you can spread the bits apart to insert a coupling (unlikely). A repair coupling is tougher to utilize, as the cement can make it stick before you get things positioned properly, the banded couplings don't have that problem and are just easier to use.

Thanks. Didn't think about the use of banded coupling which will probably making things easier.