New Sink for Bathroom

[Chowsman]

Please see the attached picture. I would like to add a sink in the location shown. I'm thinking it could be tied into the 2" stack coming down from the upper bathroom sink. What is the maximum distance from the stack the sink can be without adding a vent? Thanks

 

[Terry]

The sink needs to be vented "before" it enters the 2" "waste" stack.
Normally you would extend the vent to the second floor and tie in at 42" above the second floor.
If you can't do that, then an AAV.
Auto Air Vent

 

[Sponsor]

 

[Chowsman]

The sink needs to be vented "before" it enters the 2" "waste" stack.
Normally you would extend the vent to the second floor and tie in at 42" above the second floor.
If you can't do that, then an AAV.
Auto Air Vent

Not questioning your expertise but why does the sink need to be vented if it's only 2ft from the stack?

 

[Terry]

Not questioning your expertise but why does the sink need to be vented if it's only 2ft from the stack?

First tell me what you do for a living.

 

[Chowsman]

First tell me what you do for a living.

Semi-retired renovator. The reason I ask is that I removed a sink on the other side of the room which you can't see that was connected to another stack and there was no venting as you describe. The house was built in 69 so w=maybe the code has changed?

 

[Terry]

I've been a licensed plumber since the 70's
All plumbing fixtures need to be vented, and that venting takes place on the same floor. We don't use the upstairs plumbing as a vent, nor do we use the downstairs vents for waste lines.
You can do same floor wet venting for bathroom groups, "On The Same Floor"
They even limit tail pieces for vertical length, as that's a problem with siphoning too. For instance, a washer trap needs to be on the same floor as the washer, it can't be below the floor.
I can't explain why you found what you found. Finding it doesn't make it right.

 

[Chowsman]

I've been a licensed plumber since the 70's
All plumbing fixtures need to be vented, and that venting takes place on the same floor. We don't use the upstairs plumbing as a vent, nor do we use the downstairs vents for waste lines.
You can do same floor wet venting for bathroom groups, "On The Same Floor"
They even limit tail pieces for vertical length, as that's a problem with siphoning too. For instance, a washer trap needs to be on the same floor as the washer, it can't be below the floor.
I can't explain why you found what you found. Finding it doesn't make it right.

Hi Terry; so I took a pano of the room in question. So as you can see by the picture the Old Sink was on the other side of the room and ties into a 2" vent stack. There was also a sink on the other side of the wall. This stack (marked in Orange) goes up through the floor above extending beyond roof line. Can I place my new sink in the location indicated and run a vent line up as shown (in grey) and tie into the Orange Vent line? Thanks

 

[Terry]

Yes, you can tie into the existing vent stack.

 

[Chowsman]

Yes, you can tie into the existing vent stack.

Thanks a lot, buy you a beer the next time I am in Seattle area. Be safe.