Wet venting WC thru lav in new basement 1/2 bath

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by bindslind, Feb 23, 2013.

  1. bindslind

    bindslind New Member

    Messages:
    5
    Location:
    Melrose, MA
    Hey guys,

    I'm planning out the dmv for a new basement half-bath and, as you can see in the drawing below, I have the wc wet venting out via the lav. Just to note, the vent will then continue directly up to the attic where it will tie into an existing 2" that terminates above the roof.

    Got two questions:

    1. My code check book says that having a wet vent downstream from the wc isn't upc compliant. Is this the case in my layout?

    2. After vent continues on from the lav drain can I reduce down to 1 1/2" to snake up to the attic?

    Thanks

    basement_bath_03.jpg
  2. Hammerlane

    Hammerlane New Member

    Messages:
    252
    Location:
    Ohio
    I believe a wet vented fixture requires a larger drain pipe diameter in its wet portion and after that it could be reduced to the 1.5"

    Attached Files:

  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,534
    Location:
    Cave Creek, Arizona
    Run the 3" TO the lavatory install a 3x2 combo on its back, continue the 3" with an offset to the toilet. Then, put a 2x1 1/2" sanitary tee in the riser and continue 2" up for the vent. The toilet vent must be 2".
  4. bindslind

    bindslind New Member

    Messages:
    5
    Location:
    Melrose, MA
    I was going to do something like your suggestion originally, but after I found the main thru the floor(hence found it's angle and slope) figure I needed to change my strategy.

    Below's an image that shows the depths. I guess running the 3" directly from the toilet to lav then directly to 4.5" tie-in shouldn't increase the distance so much that it compromise's the correct slope I'll need.

    hj: When you say "offset to toilet" you are talking about pipe direction not the flange?

    basement_bath_2_03.jpg
    Last edited: Feb 24, 2013
  5. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,136
    Location:
    Maine
    You are in Massachusetts, mass has its own code and you cannot do your own plumbing there so anything you do will be wrong.
  6. bindslind

    bindslind New Member

    Messages:
    5
    Location:
    Melrose, MA
    I guess that's correct more or less, but regardless of whether an inspection is involved I like to follow the code.
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,136
    Location:
    Maine
    You don't even know what your code is. Why wouldn't an inspection be involved.? Do you understand that illegal, Un-permitted and un-inspected work can cause your insurance company to cancel your policy, may devalue your property if you decide to re-sell and possibly cause property damage and illness to your family and others in the neighborhood?
  8. bindslind

    bindslind New Member

    Messages:
    5
    Location:
    Melrose, MA
    If I want to tackle this job myself and save $1000+, a permit cannot be involved since I believe I'm not eligible to pull one according to MA.

    Also if I understand all the risks, among the ones you mentioned, as the homeowner I can do this job.

    Not knowing the code is partly why all us DIY's are here asking questions anyway.
  9. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,136
    Location:
    Maine
    Well folks, there you go.

    So when do you decide to obey the law? When it's morally and financially inconvenient I guess the law doesn't apply to you. It's a misdemeanor to plumb in Massachusetts without a license.
    Last edited: Feb 24, 2013
  10. bindslind

    bindslind New Member

    Messages:
    5
    Location:
    Melrose, MA
    Tom: Point taken. Thanks.

    I didn't expect to get a lesson in morality on my first post to the forum, but alas, I think may look into hiring a pro for the rough-in and come away a better man!
  11. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,136
    Location:
    Maine
    Well I hope you are sincere. As a plumber my first priority is to protect the health and safety of the public
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