Basement bath/laundry

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Kestrel, Aug 22, 2011.

  1. Kestrel

    Kestrel New Member

    Joined:
    Aug 16, 2011
    Location:
    Seattle
    Hello again wise plumbers...

    As I've posted recently, I'm in the starting stages of a basement remodel, to include a new bathroom. To do so requires an ejector, and some other concrete cracking/excavation - for the toilet and shower, at least.

    In an effort to minimize the concrete work, the following struck me: Can I have a shower and laundry next to each other; the shower with a 2" trap, and its own vent in the wall bounding the shower, and the laundry with a 2" standpipe and trap, and its own vent, with the drainage of the laundry then flowing via a santee into the vent pipe of the shower?

    Like this:
     

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  2. Tom Sawyer

    Tom Sawyer In the Trades

    Joined:
    Nov 29, 2010
    Location:
    Maine
    No you can not.
     
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  4. Kestrel

    Kestrel New Member

    Joined:
    Aug 16, 2011
    Location:
    Seattle
    Drat.

    Is that because the laundry hook-up makes the shower a wet vent?
     
  5. Kestrel

    Kestrel New Member

    Joined:
    Aug 16, 2011
    Location:
    Seattle
    Would this work?
     

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  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Occupation:
    Retired Systems engineer for defense industry.
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    New England
    It's not technically a wet vent (as I understand it), that's where multiple fixtures are attached to the same drain line that may only have one vent. On your proposed situation, the only vent is being asked to be a drain...not the same thing. Once a vent becomes a vent, it must always remain a vent - you can't use it as a drain.
     
  7. dlarrivee

    dlarrivee New Member

    Joined:
    Jun 28, 2009
    Occupation:
    Foam/Fireproofing/Acoustical
    Location:
    Canada
    You've already made it easy by deciding to have the laundry close to the bathroom, now don't make it hard by trying to use a vent as a drain.

    You're going to have to remove concrete no matter what, why not do it all once and do it right?
     
  8. Tom Sawyer

    Tom Sawyer In the Trades

    Joined:
    Nov 29, 2010
    Location:
    Maine
    Your 2nd drawing will work and meet code.
     
  9. Kestrel

    Kestrel New Member

    Joined:
    Aug 16, 2011
    Location:
    Seattle
    Thanks everyone - expert advice much appreciated.
    The other day I posted a diagram that was generally well received, including wet venting a lav into the toilet drain. A detail of that drawing is below.

    I'm trying to understand - it's OK to take a lav drain and drop it down the toilet's vent, but not to do the analogous and drop the laundry's drain down the shower's vent? Is that correct? Is it because the lav/toilet/shower are all a 'group' that are allowed to wet vent together, and this excludes the laundry?
     

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  10. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    NO! It is because the washer is a "high volume and flow" device, and its water going past the shower drain connection, WITHOUT a vent, could aspirate the water from the shower trap. It would NOT be vented, because you have the shower vent occulded by the water flowing from the washer. IF you could do it, you would NOT need the washing machine vent in the first place. I have one customer who has a "high flow" device connected to his toilet's vent, apparently because it was the "easiest" place to connect it, and every time water discharges it sucks all the water out of the toilet.
     
    Last edited: Aug 23, 2011
  11. dlarrivee

    dlarrivee New Member

    Joined:
    Jun 28, 2009
    Occupation:
    Foam/Fireproofing/Acoustical
    Location:
    Canada
    Why you keep insisting on using the vents as drains?
     
  12. Kestrel

    Kestrel New Member

    Joined:
    Aug 16, 2011
    Location:
    Seattle
    I'm not insisting on anything - I'm just trying to learn.
    I suppose I come up with some of these strategies because I don't like concrete work, and I'm trying to minimize it. It's dusty and dirty, the debris is heavy - I just don't enjoy doing it as much as framing or running pipe or installing windows. I was looking for the design scheme for this bathroom that would allow the least amount of concrete break-up and refilling, that's all.
    It also seems that using vents for drains - like the lav into the toilet - was OK. I didn't know how far this extended. I totally understand now about the high flow nature of the original scheme above not being a good or workable idea.
    Thanks
     
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