How to vent this basement "island" wet bar - picture.

http://www.patrickdaley.com/wpg2?g2_view=core:DownloadItem&g2_itemId=42781 - Rendering, look at this first.
http://www.patrickdaley.com/wpg2?g2_view=core:DownloadItem&g2_itemId=42322 - Actual picture.
http://www.patrickdaley.com/wpg2?g2_view=core:DownloadItem&g2_itemId=42757 - Actual picture.

So what you're looking at is part of my basement except for the toilet, tub, and sink, which are actually on the first floor. (I just included those fixtures for perspective). The waste stack from the first floor bathroom runs inside the blue column/soffit and under the basement slab. The waste drain and supply lines are right there so getting that part done for a wet bar shouldn't be too bad. The cabinets are not installed yet, obviously. The wet bar vent will get tied in up on the first floor to the vent stack for the bathroom. I'd like to run the wet bar vent vertically inside the existing column/soffit that contains the waste drain and then inside the wall as close to the current vent stack as possible. My biggest question is how to get there. At some point I will have to run the wet bar vent horizontally to get over to the vent stack. Would this setup count as an island where a loop vent could be used? I'm not sure how else to run this because if I went straight up with the vent from the basement floor I'd end up in the middle of the floor in a bedroom. Another point of clarification I could use is whether the 6" rule applies to just the wet bar or to all of the fixtures on the first floor, too.

I do have a quote from a plumbing company to do the heavy lifting, but we haven't gone over in detail how they plan to run the vent and I'd like to have some ideas on how it could be done. I'm in Minnesota, by the way.

Thanks!

IF a plumber is going to do the job, HE is NOT going to ASK YOU how to run the vent, so your labors will be in vain.

No offense, but I really don't understand your response. I'm the homeowner and contractor on the rest of the project. (And I do know what I'm doing outside of plumbing; the electrical and building permits are finaled). If I'm paying someone to come in to do work on my project in my house of course I expect some collaboration as to how the job is going to get done.

You're basically telling me that when you go into a job site you ignore all of the other trades people and just work inside of a vacuum?

In either case, if anyone thinks it's feasible to get the wet bar vent inside the existing column I'd appreciate your thoughts on it; I really don't want a second column/soffit.

Here's the answer I have from the company that has bid out the job. I'm assuming the 42" is based on critical distance for the 1-1/2" drain size, but don't you still need to be above the spill line even if you're inside of the critical distance?

"Our objective would be to tie the vent in with an existing vent. I don’t clearly remember what my plan may have been. Keep these things in mind. I “loop†or island vent will not be allowed. We can run a vent horizontal but the horizontal drain must go vertical after 42â€. Once it gets 6†above the spill line of the sink, it can go horizontal for as long as we need, while keeping the required pitch. Therefore, if I understand you correctly, in order for the vent to run up the vertical column, the sink would need to be within 42†of that column. We could run up that column, above the main floor lav sink, and then tie in."

Had another plumbing company out today. They didn't think breaking up the floor was necessary. They thought they could just snap the stack inside of that column and add a tee to service the bar sink drain and then go up through the column to the upstairs to tie in the vent. I'm all for not grinding up the asbestos tiles on the floor if possible. Two very different approaches from two different companies; not sure which is "better".

What #1 is saying is that the trap arm can be a max of 42" from the trap to the vent. If your sink is within that distance to the center of the column, you should be fine.

It's the vent itself that cannot run horizontally until it reaches 6" above the flood plane.

Thanks for that, fellow cheesehead!

Any opinion on the two different approaches that have been offered?

They sound the same to me?

As long as you are within 42" from the trap to the vent I would do it like this:

Trap -> Wye (on its back for the vent) -> then tie into main stack with san-t.

Getting the san-t in might be hard. And go with 2" pipe, that will help.

from the picture it looks like the sink and that column are not attached ? So running a vent up that column is not going to be possible at all. Like HJ said, why not let the plumber do his job?

to know what options you have, you can ask about two separate things.

One is the vent. I see three ways possible routes to get that sink vented.

Another is the drain. No comment from me on that.

For both of these two subjects, you will be dependent on your plumber, who is on site and can see things in reality. Drawings are not the same thing as reality. Being there is better than being on the internet. The plumber will know best.

It is possible that the plumber will have a bias more in favor of doing it one way or another. With a short comment from you the plumber might agree to do the vent another way. No comment from me about the drain.


Venting the sink can be done by 1/ putting the trap nearer to the column, 2/ doing an undercounter island loop, 3/ building a 9" divider wall or segment of raised counter, which hides the sink (while it also contains the vent). But this may be all wrong, because I haven't looked at the total distance from your sink drain to the vent stack. That number needs to be calculated before anyone will know what will work.