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beardz · Apr 20, 2010, 11:24 AM

I am planning a kitchen remodel in which I will move the sink/dishwasher from the wall to an island about 10' from the current 2" stack in the wall. I also have a 2" iron stack running from my second floor showers through my kitchen to the basement (currently enclosed in a column that will run through the new island). I originally thought I could drain/vent the new sink through this 2" stack, but it sounds like I can't because this is a "wet" pipe and cannot also be used as a vent.

It seems that I could use the 2" stack inside the column to drain the new sink, but I will then have to run a revent up through the second floor to somewhere above the shower. Or, I could loop vent the new kitchen sink back to its original stack in the kitchen wall. The loop vent seems easier...

My question then, is there a maximum distance that I can loop vent from the new island sink to the existing kitchen drain stack? Is 10'-13' to far?

Any other recommendations?

truck 41 · Apr 20, 2010, 10:16 PM

Check your local plumbing code to see if a footvent is required, you should be OK as long as you have a 1/4" per ft. sloap, and the loop vent.

massplumber2008 · Apr 21, 2010, 04:56 AM

Hi Beardz:

Sounds like you have a good understanding of how plumbing works. Cutting into the 2" sounds fine and then vent as you are suggesting or perhaps you could use a PROVENT. A provent (or AAV) is not legal in all states so check your local codes, but if acceptable this mechanical vent simply screws into the pipe just above the trap.. see image. Although not ideal, that would take care of the venting pretty easy.

Otherwise, please describe how you plan to get the vent relooped back to the old vent... curious how you plan that as this is an island sink..? I understand the vent going upstairs and connecting in at 6 inches above the flood level of the SINK (not the shower), but how can you revent by looping back? Let me know... OK?

Mark

speedball1 · Apr 21, 2010, 05:05 AM

If your area doesn't allow AAV's here's how to rough for a island sink; How To Plumb An Island Sink: How To Plumb An Island Sink | Plumbing Projects | Reader's Digest

... My question then, is there a maximum distance that I can loop vent from the new island sink to the existing kitchen drain stack?

Not in my code book.
Good luck, Tom

beardz · Apr 21, 2010, 10:57 AM

Thanks massplumber and speedball,
I've read your comments on similar posts and appreciate your expertise.

To answer your question, massplumber:

Otherwise, please describe how you plan to get the vent relooped back to the old vent... curious how you plan that as this is an island sink..?

I had planned to run the vent and drain into the basement, then into the stack from the current kitchen sink, closing off the current sink's tee and using the whole stack only as the vent/drain for the island, as I found online in this tutorial...
Black & Decker Power Tools

However, in another post, Milo (the California plumber) said it violates code because the vent connects below the overflow level of the sink. Is this true? If so, I could try to send the vent up higher into that wall to connect to my current kitchen stack above the overflow level.

massplumber2008 · Apr 21, 2010, 05:04 PM

Hi Beardz...

I'll tell you, I have a few different ways to do this. One is very much like Tom's (see image) and another is closer to black and deckers' version (click on massislandvent2.pdf, below left). I can present a couple other ways, too... ;)

Since you really seem willing to do this job according to best practices/priciples I would suggest that you find out exactly how they pipe an island sink up in your area.

If you cap off the old kitchen sink and use the old stack as a vent stack then it sounds to me like you meet the 6 inches above flood level rim requirement that Milo talked about... as long as nothing above this old vent... right?

Anyway, maybe if you tell us what code you fall under we can give better info... maybe? Otherwise, you should be able to find the info. Online via Google

Back to you...

Mark

beardz · Apr 22, 2010, 05:56 AM

Thanks again Mark. I live in the Saint Louis, MO, area.
In my last house, I did quite a bit of "creative" DIY plumbing, but we plan on being in this one for a while, so I'd like to do things right.

I adapted your picture to reflect my plans:

Name: island plumbing plan.jpg
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Name: island plumbing plan.jpg
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Size: 51.4 KB

This pretty much follows the Black and Decker suggestions. Let me know if you see any problems. Are you saying that even though the vent hits the stack in the basement its OK because nothing else drains above it? I thought maybe I needed to take my foot vent up into the kitchen wall and attach it to the stack above the flood level of the island sink. Alternatively, I thought maybe I could use the 2" shower stack to drain and the old kitchen sink line to vent? Would that change anything?

speedball1 · Apr 22, 2010, 06:07 AM

Looks good to me. Good luck, Tom

massplumber2008 · Apr 22, 2010, 02:48 PM

Looks good to me, too Tom!

Beardz, you don't need to run the vent pipe up inside the wall as the vent is already above the flood level rim of the sink... heck, it goes up to the 2nd floor or higher... right? Think of it in terms of the old sink... the vent just continued up right as it is now... same applies here.

If, as an example, you wanted to reconnect the old sink and still install a sink in the island then you would have to open up the wall and take the island sink vent and connect that 6" above the flood level rim of the old sink. Hopefully, that clears that up... ;)

Back to you...

Mark

Milo Dolezal · Apr 22, 2010, 06:19 PM

I would just add: do not reduce the vent to 1 1/2" until you get above the floor. Reduce after 2" clean out.

Also, in your drawing #7 you don't show clean outs on the loop vent, inside the cabinet. Install one on the drain and other on the vent. Slope below-the-floor vent upwards...

Otherwise, looks good... Milo

beardz · Apr 23, 2010, 06:25 AM

Thanks for all the help, guys. I was terrified that someone would have to tear up my second floor to run a revent above the bathrooms. This should be much easier.

Final question... In my island, I was planning on putting the plumbing inside a knee-wall that backs the actual cabinets in order to conceal all of the pipes except for the stub-out. If I do that, how do I handle the cleanouts on the loop? Do I put them there even though they will be difficult to access, or should I just keep the loop inside the cabinets?

Milo Dolezal · Apr 23, 2010, 08:19 AM

Better to have Clean Outs in hard-to-access area than not have them at all. You will appreciate them in times of need.

We do it both ways. Most of the time we install loop on the inside of the cabinet and against the back wall. Here, make sure you plan carefully with location of angle stops. Also, sometimes Garbage Disposer may interfere with the loop.

But of course, it is cleaner installation if you put the entire loop inside the pony-wall. You can extend Clean Outs just like drain through the cabinet wall and terminate them inside the cabinet.

Good luck... and revisit with progress photos ! Milo

beardz · Apr 23, 2010, 08:40 PM

Thanks again, Milo. It just hit me to put most of the loop inside the short wall but behind the dishwasher, so accessing the clean-outs will just require sliding it out. Hopefully the job will go half as easy as it sounds now when I try this next month.

Widdershins · Apr 24, 2010, 07:52 AM

I'm pretty sure Saint Louis has adopted the Uniform Plumbing Code, beardz, in which case you can likely use an AAV with prior approval of the Local Authority.

Don't get me wrong, you seem to have a pretty good grasp of the installation procedures for installing a Foot-Vent, but why go through all of this rigamarole if you don't have to?

And if you tie into the old 2" kitchen drain line and leave the old 1-1/2" vent in place, you have satisfied the auxiliary/relief vent requirement adopted by most municipalities who have given only partial approval for the use of AAV's.

Widdershins · Apr 24, 2010, 07:59 AM

Originally Posted by Milo Dolezal

I would just add: do not reduce the vent to 1 1/2" until you get above the floor. Reduce after 2" clean out.

Also, in your drawing #7 you don't show clean outs on the loop vent, inside the cabinet. Install one on the drain and other on the vent. Slope below-the-floor vent upwards...

Otherwise, looks good...Milo

Milo -- Has California banned AAV's altogether, or are you allowed to use them in some instances with prior approval?