Single to double vanity - better way? Illinois

Discussion in 'Illinois Plumbing Code Questions' started by john-ee, Jan 2, 2010.

  1. john-ee

    john-ee New Member

    Messages:
    3
    Location:
    IL
    Hi,

    Thanks for the great forum and advice. I'm looking to move some supply lines to transition from a single to a double vanity. The picture below is self-explanatory about what I'm thinking and I'd appreciate some experienced input to validate my plan. The drain used to be in the center of the existing supplies and I've already reconfigured it for the dual sinks with the added vent line. There is a 28" run from the left 1-1/2" drain to the center vent so I think I'm OK in that regard. I saw Terry's double vanity example picture with the black PVC drains and started down that route but I hit a snag when I realized that I didn't have quite enough space for everything to fit comfortably when overlapping the 1/2" supplies. There's only enough room for one supply in front and one supply behind the PVC. I then wanted to just move the tees below and create two new lines off of the 3/4" below, but the finished ceiling, the duct work, and the beam make that harder than I'd like. Does what I propose look unprofessional and if so, could you help me with something that works better?

    Thanks,
    -John-

    Bath 005.jpg
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,053
    Location:
    Bothell, Washington
    No plumbing inspector would pass that setup.

    Normally a plumber would use a double fixture fitting on a double lav, this way both lavs would be vented.

    [​IMG]
    Last edited: Jan 3, 2010
  3. wallskev

    wallskev New Member

    Messages:
    72
    Location:
    North Carolina,USA
    Becasue is not a resaon why !

    Terry:
    Would it be better to give a short reason why, other then a statement such as "No plumbing inspector would pass that setup."..:confused:

    This person nees to know "WHY" and if possible, like he stated " .....and if so, could you help me with something that works better ...";)
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    dwv

    "No inspector would approve that setup", period. The only sink "vented" is the left one. The left sink flows past the right one negating the effect of the vent on that trap. As far as the water piping is concerned, your drawing will work, although it seems to be much more complex than necessary.
  5. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    You weren't thinking about it you did it...it's all cut and glued up....we don't know what state and or city you live in so we would have no idea what would pass and what wouldn't....
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    code

    Pass/fail depends on the code, and some of them are very lenient when it comes to hydraulic issues.
  7. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Besides the vent issue, how many fixtures are on those 1/2" lines?
  8. RTAPlumbing

    RTAPlumbing Plumber

    Messages:
    27
    Location:
    lawrenceville, GA
    it would probably pass where i live if the arm was 2'' pipe. your tee for your vent should be the other way
    Last edited: Jan 3, 2010
  9. john-ee

    john-ee New Member

    Messages:
    3
    Location:
    IL
    Thanks for all of the replies.

    The drain is glued and done, but I'm certainly not opposed to cutting out a few dollars worth of fittings to do it right. I'll use a double fixture tee and run the vent vertical to above the flood-level of the vanity and tie into the existing 2" vent on the right.

    Would running the centered drain from the two sinks back to the right to the existing drain be alright? I'd like to avoid cutting into the 3" drain in the basement. Since this 3" drain is pretty unmovable, getting a fitting inserted sounds somewhat difficult.

    The current 1/2" supply lines are fed from two 3/4" lines running left to right in the picture. They continue on to the right for about a foot past what you see where they tee to the shower and tub toward the bottom of the picture and to the right for the toilet and a currently unused laundry hookup. The cold is 3/4" in all directions but the hot is 3/4" to the tee then 1/2" off of that.

    Thanks again,
    -John-
  10. Terry

    Terry Administrator Staff Member

    Messages:
    15,053
    Location:
    Bothell, Washington
    wallskev, At 12:30 in the morning I'm not going to give a full reason. Especially when he has seen the right way to have done this.
    Which, by the way he could still do.
    The fixture cross would have been closer to the right.
    You can go 42" with each trap arm.

    I have a second option below that would pass inspection with the 2" waste line coming up from the floor. As long as that wasn't a vent for downstairs.
    The tee for the first lav would be above the first tee, and then a tee at 42" to revent the second lav.

    Attached Files:

  11. john-ee

    john-ee New Member

    Messages:
    3
    Location:
    IL
    Thanks Terry. I'm going to redo it with the fixture fitting and run the drain over to the 2" line to the right, unless that creates a problem as well. The tee on that line was already there for the original vanity drain and this serves as the water closet vent as well. Nothing else below.

    Thanks,
    -John-
  12. Doherty Plumbing

    Doherty Plumbing Journeyman & Gas Fitter

    Messages:
    810
    Location:
    Penticton, BC
    You shoulda just circuit vented the two sinks. Woulda been quick and easy.

    Yes I would make the main line a min of 2" however up here that line would just have to be sized as a wet vent and it would techinically be ok on 1.5".
    Plumbing in Canada


    [​IMG]
    Last edited by a moderator: Jan 4, 2010
  13. Terry

    Terry Administrator Staff Member

    Messages:
    15,053
    Location:
    Bothell, Washington
    [​IMG]
    Here's another take on converting a single lav to a double lav
  14. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    ???????????

    Without a ruler in the picture, it is just a guess, but given the distance of the horizontal vent above the openings for the sink drains, I am guessing that it is neither 42" above the floor, NOR 6" above the sink rims.
  15. xr4ti

    xr4ti New Member

    Messages:
    26
    Location:
    Wisconsin
    Double vanity at a child daycare? :)
  16. Terry

    Terry Administrator Staff Member

    Messages:
    15,053
    Location:
    Bothell, Washington
    I thought it looked low too.
    That was a picture sent to me by someone that was installing vessel sinks.

    She is having drain problems related to the small grid drains.

    Yeah, must be a tiny daycare bathroom.

    I believe she said the work had been done by a "Handyman".

    More drywall should have been cut, and the revent 6" higher then the vessel sinks.
  17. Winslow

    Winslow Plumber

    Messages:
    450
    Location:
    Hawaii
    The way some of them grid drains are constructed the sinks won't drain properly, they drain slowly then when enough head pressure builds up it dumps. Not sure if maybe the openings in the grid don't equal the cross section of the drain as required, but Ive run into that problem before.

    Regarding the the picture if the furthest sink was within 3 1/2 feet I would stack the tee's and wet vent the lower drain.
    Last edited: Jan 15, 2010
  18. Terry

    Terry Administrator Staff Member

    Messages:
    15,053
    Location:
    Bothell, Washington
    One more way.

    [​IMG]
  19. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    quote; Double vanity at a child daycare?

    Codes do NOT make exceptions for a daycare center. What happens when it becomes an "adult facility" and the sinks are raised? That is why the code says, "42" or 6" above the sink rim, whichever is HIGHER", they are considering what COULD happen down the road, NOT what is happening now. The problem with grid stainers is that the openings are not large enough to allow the air to escape while the water is trying to flow into them. Inserting a straw into a hole or making the holes larger will permit full drain flow. The same thing happens with "rainfall" shower heads which are installed perfectly flat/horizontal. There are a lot of ways to do the drainage, depending on how much time and money he wants to use.
    Last edited: Oct 16, 2010
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