Island Vent Loop Question

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Pauly79, Aug 30, 2010.

  1. Pauly79

    Pauly79 New Member

    Messages:
    1
    Location:
    Toronto, Ontario
    I'm in a two story condo, and am relocating the kitchen island.

    The kitchen is on the second level, and the the current set-up involves an underfloor p-trap connected to a 2" drain that connects to a vented drain in the service wall.

    I wanted to remove the p-trap from under the floor because it causes the bulkhead its in to be an extra few inches deep and as the bulkhead will be expanding horizontally as part of my renovations, its depth will cause problems with the opening of the front door. Removing the p-trap and putting it above the slab will allow the bulkhead to be expanded without interfering with the door.

    My plumber is suggesting the use of an air admittance valve, which can be placed above the rim of the sink inside the island since the back of the island has a 6" deep ledge that rises 6" above the normal counter height.

    However, I've been reading about island vent loops and am wondering if one might work in my case. Basically, I could run a loop vent like in the attached image, except the vertical vent part of the loop would connect directly to the horizontal drain, and then that drain would be connected to a stack at the service wall, since it would be very difficult to create a new horizontal vent that connects to the stack.

    Is this possible solution, or do you need to have two separate horizontal vent and drain pipes running parallel to each other?

    Attached Files:

  2. nhmaster3015

    nhmaster3015 Master Plumber

    Messages:
    836
    Location:
    The granite state
    Here's my take on island loop venting. I don't like it. I don't like it because even with the proper clean-outs, if part of the vent does plug up no one will even know. ( especially if there is a garbage disposal installed. I would much rather see a waste stack vent or, god help me, an AAV, if the waste to vent distance is too far.
  3. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    I'm afraid it is a moot point for you.
    From what I understand the code used in Ontario likes P-Traps under the floor and does not like loop vents.
    You have to go with what is allowed by code in your location.

    [​IMG]
    Last edited by a moderator: Jan 26, 2012
  4. nhmaster3015

    nhmaster3015 Master Plumber

    Messages:
    836
    Location:
    The granite state
    I love that P trap under the floor thing. 36" stand pipe, sweet :) No worries about that trap plugging up. Oh Canada, I stand on guard for thee
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,453
    Location:
    Connecticut
    They do seem to have a lot of complaints about how loud the dishwasher draining is though... Whodda Thunk!
Similar Threads: Island Vent
Forum Title Date
Plumbing Forum, Professional & DIY Advice, Tips & Problem with very old island loop vent --- should I replace with AAV? May 3, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Unique island vent situation Apr 28, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Venting island/washer/crapper Mar 25, 2014
Plumbing Forum, Professional & DIY Advice, Tips & Possible vent issue on a kitchen island with kitchen sink in it Feb 2, 2014
Plumbing Forum, Professional & DIY Advice, Tips & non-island loop vent Oct 30, 2013

Share This Page