DIY Kitchen Island plumbing Vent question

Users who are viewing this thread

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
I am in the process of remodeling my kitchen. My current sink is not far from the new location, but I had to remove a wall. This wall had the plumbing vent inside of it. Now I need to find a new location for the vent. What I cant seemed to grasp is the size of the pipe I need to use and how far the vent can be from the new location. The drain runs towards the west side of the house and the vent runs towards the east side. If I run the vent towards the north wall, I will need to run the vent back towards the south wall to connect to its original position. If I run it towards the west side wall, i will need to run it back to the east side to connect to the original vent pipe location.

Does it matter which way I run it?
What size pipe for 10 ft ceilings? The vent pipe is approx 2 inches and the drian pipe is approx 3. (I will double check. )
vent_drain pipe diagram.PNG
 

wwhitney

In the Trades
Messages
5,661
Reaction score
1,468
Points
113
Location
Berkeley, CA
You don't show what's on the other side of the wall that was removed, but from the title it sounds like the peninsula is now an island? Then you'll be using an island loop vent. [Or if I recall, Maryland uses the IPC, and you could just use an AAV in the sink cabinet.]

Which way do the floor and ceiling joists run? If they run left-right, then it would make sense to use the left-right blue line in your drawing. The vent would run under the floor to the wall at the left (rising, so that if it filled with water, it would drain back to the extra vent/drain connection under the sink), then rise up the wall (with an accessible cleanout), then run in the ceiling joists from right to left to get back to the existing vent connection.

For a kitchen sink and dishwasher a 1-1/2" vent (1.9" OD) and 2" drain (2.375" OD) would be sufficient. If the existing drain is larger, you can tie into it with new 2" work. If the existing vent is larger, you might want to just run 1-1/2" for the new work.

Cheers, Wayne
 

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
The wall that was removed has the living room on the right (east), kitchen on the left (west).

Yes, it was a peninsula and will be converted to an island. I was thinking vent loop, but the AAV appears to be much simpler and quite the space saver. Thanks!

The floor joist and ceiling joist run north to south. The original drain pipe runs below the floor joist, not in between. I imagine either direction could work, but I am finding it better to run it towards the north wall. I have a question about angles though. Should I run it directly back to the original vent pipe in the attic or run it in more of a 45 degree angle.

kitchen vent diagram2_.png
 

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
Also, it astounds me how much knowledge professionals have. I look at something, read, read, and read more...still confused. Then I have a professional look at it for 2 seconds and they are so helpful. I needed help with the electrical aspect of the kitchen and laid out a plan. I invited my electrician friend over and thought he was going to say I was nuts. It didn't phase him at all. In fact he came up with a better plan in minutes and made everything so much easier. I just wish I had a plumber friend! THANKS for the help!
 

wwhitney

In the Trades
Messages
5,661
Reaction score
1,468
Points
113
Location
Berkeley, CA
Should I run it directly back to the original vent pipe in the attic or run it in more of a 45 degree angle.
So the horizontal vent should be sloped so that if water got into it would run back to the drain, i.e. you can think of the vent as rising at 1/4" per foot as it goes towards the roof exit. [Particularly critical for the "foot" portion of the island loop vent, but also true in the attic.]

Thus my inclination would be come out of the wall into the ceiling joist bay at a height where the vent can run down the joist bay while rising at 1/4" per foot, and then where it needs to turn to perpendicular to the joists it has risen to clear the first joist by maybe 1/4".

In other words, not the angle. Of course, that assumes a wide open attic with no obstructions to avoid, so you could run it differently if preferred.

Cheers, Wayne
 

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
Wayne, Thanks. That makes a lot of sense. I'll be sure to do that. I might have to make modifications to the current set up because the horizontal vent in the attic currently runs flat on top of the trusses in the attic. I did remove the original vent and when I did I was surprised that a little water came out because I thought that would have been in the drain. Now I understand why and what I can do to fix it. Thanks again.
 

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
I wanted to add an additional diagram to ensure everything is done correctly. The vent pipe runs 8ft away from drain pipe until it turns 90 degrees and becomes vertical. It then turns another 90 and runs horizontal to the original pipe which turn 90 degrees again towards the vent stack. Its practically right over top the drain and where the vent started. This is the only option if I build a loop vent. The drain pipe is 2 inch and vent pipe is 1 1/2. I have found conflicting information on distance and pipe width. so I just wanted to confirm if this would work.
 

Attachments

  • kitchen side view with vent pipe diagram.jpg
    kitchen side view with vent pipe diagram.jpg
    69.7 KB · Views: 55
  • kitchen side view with vent pipe diagram.jpg
    kitchen side view with vent pipe diagram.jpg
    69.7 KB · Views: 49

Kmcogar

New Member
Messages
9
Reaction score
0
Points
1
Location
Maryland
Also, to clarify the AAV. If I was to install the AAV. Is a vent stack connection needed? I assumed that eliminates the need for it which is why plumbers use it. Seems too easy...
 

wwhitney

In the Trades
Messages
5,661
Reaction score
1,468
Points
113
Location
Berkeley, CA
On the loop vent, the lengths noted on your diagram are not a problem.

The horizontal below floor vent is called the foot vent. The the main requirements are (a) that the foot vent be sloped towards a connection to a drain and (b) that the foot vent be roddable (snakeable). For (a) typically the drain is the horizontal sink drain, which means the foot vent is higher than the horizontal sink drain and rises as it moves away from the island. For (b), typically a cleanout is installed in the vertical vent in the wall.


On the AAV if you use one under the sink (at least 4" above the trap arm), then the whole loop vent goes away. It's that simple, and you just have the drain to deal with as usual.

Cheers, Wayne
 

Terry

The Plumbing Wizard
Staff member
Messages
29,701
Reaction score
3,257
Points
113
Location
Bothell, Washington
Website
terrylove.com
Also, to clarify the AAV. If I was to install the AAV. Is a vent stack connection needed? I assumed that eliminates the need for it which is why plumbers use it. Seems too easy...

Many new homes where the kitchen is by itself, on an island for example, I'm seeing AAV's.
It is the simple way of doing it now. Not all codes allow for them though. They do work though.
 

Master Plumber Mark

Sensitivity trainer and plumber of mens souls
Messages
5,417
Reaction score
307
Points
83
Location
indianapolis indiana - land of the free, home of
Website
www.weilhammerplumbing.com
Many new homes where the kitchen is by itself, on an island for example, I'm seeing AAV's.
It is the simple way of doing it now. Not all codes allow for them though. They do work though.

Most new homes we see AAVs under the sinks
Around here I have also seen all sorts of stupid things being done to avoid difficult venting
like running a 3 inch PVC line in the slab floor to the kitchen sink and just installing
an AAV under the sink.... For some reason they got it in their minds that the 3 inch is so large it will never siphon.....
But it can get totally stopped up with grease or any kind of cooking oils that won't move without using a power jetter on the line..
I found this out the hard way one time........

You can run a 2 inch PVC drain line to the island sink and just install a cleanout and an AAV under the sink and
it will work for a hundred years... most likely
 
Last edited:
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