Venting new main floor bath.. will this work??

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by EldonP, Jan 31, 2014.

  1. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    Hi All,

    I'm trying to plan a new bathroom on our main floor that's directly below the one on our main floor. The pictures below say it all, but in essence I'm trying to vent a sink and toilet without running pipes up the wall at the fixture locations. I've got lots of space in the basement to work with, so I've come up with a few ideas.. Will any/all of these work for me?

    In terms of local code, I haven't found a good guide, so I'm trying to wade through the actual code as I can. It looks to me like any of these configurations could arguably meet the maximum length to trap. However, there is a bit in there that says that the vent must attach to the fixture above its flood line. I don't understand how this is possible considering that the flood line of a typical vanity is pretty much level with the outer surface of the vanity.

    As I said, I'm finding the plumbing code opaque, so any advice would be much appreciated!

    Thanks,
    Eldon

    Attached Files:

  2. Hammerlane

    Hammerlane New Member

    Messages:
    252
    Location:
    Ohio
    Your figure #1 is not effectively venting the sink. I believe you need to pull the vent before the water drops vertical after the trap arm.

    Same with figure #2.

    With figure #3 how long is your tailpiece length?

    One of the real plumbers will be along shortly

    Attached Files:

  3. Terry

    Terry Administrator Staff Member

    Messages:
    15,004
    Location:
    Bothell, Washington
    The vent for the lav needs to be at the level of the p-trap and trap arm.
  4. mikeplummer

    mikeplummer Plumber

    Messages:
    190
    Location:
    Ontario, Canada
    none of your sketches will meet code... # 3 is the closest as it is effectively a wet vent (assuming its sized right and fixture outlet is not too long) but in order to wet vent the lav would have to connect via continuous waste & vent....so you will need to vent the toilet separately
  5. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    From your reply and the others, I see that a vent must take off from above the trap. I'd love to do something like you propose in green, but I'm hoping to avoid running pipe in that location. This exercise may prove that this is impossible, however. We'll see..

    To answer your question, I'd estimate something like a 30" drop between the bottom of the sink and the trap. Is there a restriction on this length? I'll have to take a look at the code for this..
  6. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    Sorry, not used to the forum format.. That reply was meant for Hammerlane
  7. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    Mike, if I understand you correctly, the two issues with #3 are that the toilet needs a separate vent and the drop from the sink to the trap might be too long.

    Here's a new diagram with the toilet vent added. I'll have to look into the sink and toilet drop lengths.. Any keywords I should look out for when I try reading the code?

    I guess another solution would be to put an AAV under the sink, vent the lav per sketch 1, and call it a day?
    proposed vent 4.jpg
  8. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    A little bit of research reveals that the vertical run maximum is somewhere in the neighborhood of 24" and I'm not kneeling to wash my hands, so looks like AAV it is!
  9. Hammerlane

    Hammerlane New Member

    Messages:
    252
    Location:
    Ohio
    30" will be too much drop

    Attached Files:

  10. EldonP

    EldonP New Member

    Messages:
    6
    Location:
    Ontario
    Unless anyone figures otherwise, it's looking like this is the way to go.. Or, of course, give up the extra space in this tiny room and run pipes through the walls behind the sink.

    I still need to double check in the code whether the vent between the toilet and the stack is required.. I recall reading somewhere that a vent is required for a toilet when there are fixtures upstairs on the same stack, but this may be a regional thing. Thanks everyone who responded; added a lot to my understanding of the problem!

    PROPOSED 4.jpg
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,631
    Location:
    Cave Creek, Arizona
    quote; I still need to double check in the code whether the vent between the toilet and the stack is required.

    There is NO question about it. It IS required, and the sink AAV will be ineffective if that vent is eliminated.
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