Bathroom- Converting single vanity to double

Discussion in 'Remodel Forum & Blog' started by NewJerseyJC, Sep 2, 2008.

  1. NewJerseyJC

    NewJerseyJC New Member

    Messages:
    2
    Hi all. Hope someone can help me with this bathroom remodel.

    - Converting a single vanity to a double vanity.
    - The problem is that the new vanity has drawers in the middle (between both sinks) and cannot connect two "P traps" underneath.
    - So looks like I need to change the plumbing in the wall. A pic of the existing pluming is attached.
    - I was thinking about doing the following:
    - Putting in a T to the left of the existing drain
    - Cutting pipe and inserting 1 1/2 pvc to the right of the T
    - And then putting in an elbow to the right of the existing drain.
    - This would then give me two drains to connect two "P traps" to.
    - Existing drain would obviously be eliminated by putting in the T, the 1 1/2" pipe and new elbow.

    So will with work? Or are there other considerations and/or concerns? Any help would be greatly appreciated.

    Additional info:
    - Current plumbing is 1 1/2" pvc with one drain.
    - Vanity is 5' long. The distance between the sinks is 33" on center.
    - Local plumbing code is based on "2006 National Standard Plumbing Code" but its all greek to me here's the link http://phcc.files.cms-plus.com/Depts/Technical/2006NSPCNonIllustratedWeb.pdf

    Attached Files:

  2. Master Plumber 101

    Master Plumber 101 In the Trades

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    Location:
    Wisconsin
    That will work. Put a san tee at first connection and a 90 at your second connection. You should try to have the water line's piped to the proper location also.
  3. NO.


    You cannot inline traps.

    Find your center of the double bowl vanity, use a cross-tee with a vent going up the center and back towards the vent stack.


    You already have a trap arm that's too long for most standards by code. 3' 6" I believe is max on 1.5".


    My state follows the NPC.

    Max distance from that vent in the center would be 1' 6" which is doable.
  4. Redwood

    Redwood Master Plumber

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    Lots of things wrong with that idea!
    A sani-tee laying flat...
    Venting...
    Sheesh!

    Is that allowed in Wisconsin?

    Whats next flex traps and extensions?
    Last edited: Sep 2, 2008
  5. Redwood

    Redwood Master Plumber

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    Location:
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    New Jersey uses the National Standard Plumbing Code/2006

    I am not familiar with it!
  6. hj

    hj Moderator & Master Plumber Staff Member

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    sinks

    NO CODE allows a five foot 1 1/2" arm. And you cannot install the tee that way on any arm, much less a 1 1/2" one. The water flowing past the tee can create a venturi effect and compromise the trap seal. As a practical matter, there is almost no way to do what you want to with that drain and do it legally or properly.
  7. Master Plumber 101

    Master Plumber 101 In the Trades

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    Location:
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    Vent to trap by means of a San tee.@ 1/4" per foot 5'82.31-1 Wi state code. And yes you can tie the waste in when you common vent like that.. if your local code permits. I can't help everyone else does it backward's.
  8. hj

    hj Moderator & Master Plumber Staff Member

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    trap

    The key words are 'if your local code permits', which is seldom the case for a configuration such as this. Especially with a 1 1/2" arm. I guess since WI allows pedestal traps under the floor they allow almost anything, must use the IPC or a derivative of it.
  9. Master Plumber 101

    Master Plumber 101 In the Trades

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    Location:
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    You can countinue to talk about the pedestal trap under the floor, but I have yet to install one. I will look at the upc and start picking that apart.
  10. Redwood

    Redwood Master Plumber

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    You are in for a tough time!
    You might do better trying to pick apart the IPC!

    Your pedestal sink with the trap under the floor can be viewed here... Page 107 AKA page 19 of 90 in the PDF.
    http://www.legis.state.wi.us/rsb/code/comm/comm082_app.pdf
    Your code is unlike that of any other state in many aspects. As a rule we try to give advice that applies under most codes.
    Last edited: Sep 3, 2008
  11. NewJerseyJC

    NewJerseyJC New Member

    Messages:
    2
    Dual Drain- Proposed Configurations

    Ok. Forget about the picture I posted which shows what this currently looks like. I am attaching 3 figures of some scenarios. Let me know what you think. I think Figure A is what you were getting at. Figure B was just a thought and Figure C I'm thinking is last resort.

    Attached Files:

  12. Redwood

    Redwood Master Plumber

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    Figure C with a double fixture fitting would be correct.
    A cleanout above the double fixture fitting would be good also.
  13. hj

    hj Moderator & Master Plumber Staff Member

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    drawing

    C is the correct one using the proper fittings. One problem is that your existing drain arm is too high to do it that way, which is why I said there is no way to do it properly given your configuration. figures A & B both still have the right hand sink flowing past an unvented left hand drain.
  14. Master Plumber 101

    Master Plumber 101 In the Trades

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    Location:
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    It would be legal to connect as original pic posted if you lived in Wi. I guess we are the only one's who figured out how to run plumbing efficiently.:cool:
  15. Rich H

    Rich H Civil Engineer

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    Location:
    Wisconsin
    I'm no expert, but I live in WI and have read the code. Pretty sure san-tee cannot lie like that, only to be used in vertical applications similar to UPC - IPS says the same I'm assuming? 101 what code are you reading, COMM8X????

    Would figure A work? Probably, the chances of a venuturi effect emptying the left trap are small, esp. with the vent in the right spot now. But, code is code.
  16. Master Plumber 101

    Master Plumber 101 In the Trades

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    Location:
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    You did not read the code right if at all. 82.31(11)(b) Common vent's for horizontal drains. It's the same as the first fitting downstream of fixture can be a short sweep.If you have a single lav and is on a arm that first 90 is short sweep. First fitting only! If you have a double lav hotizontal common vent the same rule's apply for second sink tie in. How could the drain from one sink empty another on a lav, it's not located at a base of a stack where something like that is more likely to happen. The water running thru drain is not that strong to even cause such effect. Look closer before you try calling me out.
  17. Rich H

    Rich H Civil Engineer

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    Location:
    Wisconsin
    ok, simmer down :rolleyes:

    I'll be sure to check that out - like I said, I'm no expert on nuances of the code like that one.

    I agree - venturi effect as mentioned above is not likely to happen - esp. with the vent added to prevent vacuum pulling water out of left trap.

    Update - checked code quick, and it does appear that you are right, however 82.31(11)(b) also states that the vent shall be located downstream from BOTH fixtures. So, none of the above illustrations are legal in WI. But, it does appear that you can use the san-tee on it's side to connect the downstream lav to the horizontal branch.
    Last edited: Sep 4, 2008
  18. hj

    hj Moderator & Master Plumber Staff Member

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    union

    MP101, are you really a union plumber. If so that may explain it if you are one of the bench riders who waits for a big construction project before you sign on with a company. That is how I got my first job when I moved to this area. None of those guys wanted the one I got, and then after a couple of years they all were trying to bump me back onto the bench,(because the union was trying to keep me from being able to transfer in).
  19. Redwood

    Redwood Master Plumber

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    Of course any talk of Wisconsin code in this posting is off subject as New Jersey uses National Standard Code 2006.

    Somehow I believe that may just maybe be closer to UPC or, IPC in it's requirements. Just Maybe!


  20. Figure C is the one that NPC allows for your application.



    If you went with your first drawing, "worst case scenario" if you filled sink #2 and dumped it, it would suck trap #1 dry allowing sewer gases to escape. Prime example; Men shaving, women cleaning hair brushes or undergarments, bikinis.


    This is a commonly asked question in my area and the code prevents future problems down the road. Basically to install a non-fouling plumbing system.
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