Converting single bathroom sink to double sinks

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by maxxfusion, Mar 26, 2011.

  1. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    I am in the process of remodelling my bathroom. I have a 72" vanitiy with a single sink. I figured since I have the space double sinks would be really nice to have especially with kids. I made this decision late in my remodel project. I looked under the cabinet to check things out and found out that at one time there was double sinks there. So all the copper is in place. Here is my issue. I went to Lowes today and bought some ABS. I can not find the double fixture tee anywhere. I came home and googled the part. I came across the tee at Grainger but its 2 x 1 1/2 x 1 1/2 x 1 1/2. The abs pipe that runs upstairs is 1 1/2.

    So my question is does the double fixture tee i need exist in all 1 1/2? I am assuming i will have to order this online.

    Any help would be greatly appreciated.
  2. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    I just found a double sanitary tee in all 1 1/2. Not sure if I can use that?

    Attached Files:

  3. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    The 1.5 double santee will be a bear to snake. It would need a cleanout on the vent to clear the center.

    There are also ways to run it using a wye and two santees that would force the snake downhill instead of over and across to the other lav location.

    If I had 1.5" pipe, I wouldn't even bother with a cross, but instead wye off and have opposing santees to to separate trap arms and then revent at 42"

    I know that are come countries that will do it, but they must not have ever done service work. I would love to watch them try to get the snake to drop down the vertical.

    [​IMG]
    Just found this picture
    Last edited: Mar 26, 2011
  4. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    I searched this forum to find this picture from a thread created last year...
    [​IMG]
  5. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    My issue is i dont have the pipes exposed. I would need to rip out drywall to do this.

    Can i use this and some 45 degree elbows?

    [​IMG]
  6. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    How would that be any better than the double santee.

    Look at what Terry posted, do you a see a double fitting of any type there?
  7. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    No.
    That type of fitting would need to have vents on each arm. That fitting with a 45 creates an S trap.
  8. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    How do they do it in new homes?
  9. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    2 x 1.5 x 1.5 1.5 fixture cross.

    [​IMG]

    [​IMG]

    Double Lav
  10. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    So if I could find a 1.5 x 1.5 x 1.5 x 1.5 fixture cross I would be ok? I have looked a bit online and can only find the 2 x 1.5 x 1.5 1.5 fixture cross. Since I had the double sinks at one time and only have 1.5 pipe run to the bathroom can I just use a reducer to go from the 2 pipe to the existing 1.5?
  11. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    You can only increase pipe size as you drop down.
    You can't decrease.
  12. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
  13. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You certainly cannot...

    Basic rule of plumbing, you'd be creating a funnel...
  14. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    Ok thanks guys. I guess I will be removing some drywall and going off of Terrys pic he posted.
  15. SacCity

    SacCity In the Trades

    Messages:
    189
    Location:
    Sacramento, CA
    So tell me why you can not use two (2) San Tee's facing opposite directions one three inches lower than the other.
    It would result in about a 3" difference in heights for the two P-Traps but that should not be an issue, and would have a short section of a wet vent.
    Michael
  16. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Besides the venting issue, would you honestly be proud to have a tail piece under one sink that is 4" longer than the other? I would view that as a mistake as a prospective buyer of the home...
  17. Terry

    Terry Administrator Staff Member

    Messages:
    14,754
    Location:
    Bothell, Washington
    The minimum wet vent is a 2" pipe.
    To keep the venting working right, I would still separately vent them.
    Last edited: Mar 26, 2011
  18. SacCity

    SacCity In the Trades

    Messages:
    189
    Location:
    Sacramento, CA
    Minimum wet vent is 2",
    Well I screwed that one up yesterday on a repair.
    Thanks for correcting me.
    Michael
  19. maxxfusion

    maxxfusion New Member

    Messages:
    19
    Location:
    Cleveland, Ohio
    I am going to get my parts today. So just to confirm to do the method Terry recommended i will need 4 san tees and 2 45s? I already got the 2 90s.

    Also I should measure up 42" from the first san tee to connect the second san tee for the venting?
  20. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Incorrect, the offset of the stack is created with wyes and 45s, not santees... the santees are where the trap arm ties in...

    You need 2 wyes, 2 santees, 2 45s (street in his photo)... and pipe obviously...

    You already have 2 90s, but are they long radius or vent ells?

    I'd be installing a clean out below the lower wye myself.
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