Double vanity rough-in question.

Discussion in 'General Plumbing Help' started by burchis, Aug 13, 2011.

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  1. Aug 13, 2011 #1

    burchis

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    [​IMG]

    Would this arrangement of a vent-tee work in stead of double sanitary tee? I plan on wet-venting from about 5 feet away.

    Thanks for any help and/or comments.
     
  2. Aug 13, 2011 #2

    Caduceus

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    Wet venting isn't going to work in this situation. I also would recommend using a cross instead of the tee you have. Out of the top of the cross you can put a 90 ell coming out of the wall for a cleanout as long as it doesn't get blocked by drawers and is accessible. Better yet, if you can use a wye a bit lower on the vertical to go to one sink then a 90 on top of it to go to the other sink. Hope that makes sense.
    As far as venting, the vent would have to be after the trap before you change from horizontal to vertical.
    Is this a new construction house or a personal remodel project?
     
  3. Aug 13, 2011 #3

    havasu

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    Cad, since I am also preparing to convert a single basin to a double basin, could you draw out what you are describing?
     
  4. Aug 13, 2011 #4

    Caduceus

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    Havasu, I don't have the computer savvy to do that, but I am consulting my 'internet technical trainer', a.k.a The Wife, unless you can explain it.:eek:
     
  5. Aug 13, 2011 #5

    Caduceus

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    I neglected to mention that if a cross is used, a vent must be installed above it and continuing through the roof or AAVs used at each fixture after the vanity is installed.
     
  6. Aug 13, 2011 #6

    burchis

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    This is remodeling in 35 year old house. Basically I am just rearranging an old bathroom, where originally there wasn't any venting at all. I'm doing all the work myself and no county inspector will be involved.

    Could you explain what problems I would have by using the vent-tee as shown in the photo? i.e- partial waste from one drain flowing into the other drain, etc.

    Would a double-wye work as apposed to your suggestion of using a wye and 'L" combination?
     
  7. Aug 13, 2011 #7

    johnjh2o

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    With that setup the traps on the sinks will siphon allowing sewer gas to enter the home. The other concern is when trying to snake the line from under either sink the snake would just run from one sink to the other without entering the common drain line. A double Y would make drain cleaning better but you still have the same problem with sewer gas. The correct way is with a double sanitary tee with a vent coming off the top. Just because there is no inspection doesn't make what your doing any less dangerous. Codes are written for a reason. Do yourself and your family a favor and do the job correctly.

    John
     
  8. Aug 13, 2011 #8

    phishfood

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    Echoing what the others have said, with a slight twist. I would use a single sanitary tee underneath another single sanitary tee, the second one being at the height that you currently have the drains at. Then, if necessary, use a slip extension to to attach the vanity bowl to the lower drain arm.

    And make sure you vent the stack. The wet vent that you are trying to use is an S trap, disallowed by code for a reason.
     
  9. Aug 14, 2011 #9

    LiQuId

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    THERE IS NO VENT IN YOUR PICTURE... this is bad, you must install a vent.

    IF you want to use this type f configuration you must install a double sanitary T not the bull headed t that you have there and at VERY MINIMUM install an air admitance valve on the to of it, with an access door to get to it.
     
  10. Aug 14, 2011 #10

    burchis

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    Can an AAV value be used on top of a double sanitary tee which would be closed off with drywall.
     
  11. Aug 14, 2011 #11

    johnjh2o

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    No It must be accessible. But your on the right track. That can be done by putting in a access panel and covering it with a removable mirror.

    John
     
  12. Aug 14, 2011 #12

    Caduceus

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  13. Aug 14, 2011 #13

    Mr_David

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    You can try using an Island sink type of vent that is acceptable with out using a AAV
    And a couple more related pictures.

    Just a suggestion. You will have to make some modifications to get a double fixture fitting to to work

    Island-loop_vent.jpg

    dblfxtrftg.jpg

    lav_rough_double_b.jpg
     
  14. Aug 14, 2011 #14

    burchis

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    I read that there are two types of AAV's, one for a fixture and the other for system drain. So I am thinking about installing a system type AAV on top of a double sanitary tee to serve both vanities.

    What is the purpose of having access to an AAV since manufactures state they last from 30-50 years.

    Thanks for everyone keeping this post active.
     
  15. Aug 14, 2011 #15

    johnjh2o

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    For one it's code. As far as lasting for 30-50 years no one can say that as they have not been around that long. Faucet manufactures say there faucets will last for life. We all now that's not true. We were also told that the U.S.A. would never loose it's AAA rating. Need I say more. AAV's will never be as good as a vent through the roof. They are mechanical and all things mechanical at some time will fail.

    John
     
  16. Aug 14, 2011 #16

    burchis

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    So can I assume the only reason to have an access to an 'air admittance value' is in case of having to replace it?
     
  17. Aug 14, 2011 #17

    phishfood

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    If you install a vent ell on top of the double sanitary tee or even better, the double fixture fitting Mr. David showed, you can use another ell to turn back vertical once the cabinet is installed. Then install an AAV on top of that, and it will be accessible underneath the vanity.
     
  18. Aug 14, 2011 #18

    johnjh2o

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    That is the main reason. But it sounds like you feel it's not reason enough for you. It's your home and your choice to follow code or not. What seals these things is a rubber disk that is held in place by a small spring. As I said before it will fail. Good luck with your project.

    John
     
  19. Aug 14, 2011 #19

    burchis

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    Thanks to all that have contributed to this post. Let me say that I am not wanting to circumvent code or do any work incorrect. I simply post my questions to learn the 'how and why' of things. I would not be on this forum if I intended to do things any old way. I wanted input from anyone that has already experienced what I am about to do. As I received replies, new thoughts and questions came to mind and I followed those thoughts. Again thanks to all and my apologies if I came across insincere.
     
  20. Aug 14, 2011 #20

    havasu

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    No apologies are necessary. I believe the only dumb question is one that is not asked and we all learn in here!
     

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