Hooking new toilet to stack on 1st floor, below existing bathroom

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by dayster, Jun 20, 2007.

  1. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    Our house has a bathroom on the 2nd floor only. It was remodelled in the past, and all fixtures (toilet, tub, lavatory) drain through the main stack. I am planning to add a new bathroom below it on the first floor.

    The new toilet will be within 4 feet of the existing stack. Keeping in mind that there is a toilet, tub, and lavatory from the second floor above hooked to the main stack:

    -do I need a vent for the toilet or is this close enough to the main stack that it functions as a vent?
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    You must vent the toilet.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,686
    Location:
    Cave Creek, Arizona
    toilet

    It makes no difference how close it is to that pipe, that pipe is not a vent so you have to install a separate vent for the toilet.

    [​IMG]
    Last edited by a moderator: Jun 20, 2007
  4. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    Thanks for clarifying that.

    I know that the toilet on the upper floor does not have a vent, I presume this is OK since the stack above the highest fixture is considered a vent. Yes?
  5. Terry

    Terry Administrator Staff Member

    Messages:
    15,050
    Location:
    Bothell, Washington
    If you have a pipe going from the lower floor, through the roof, and there is a tee and a 90 el for the upstairs toilet, then the part above the tee, would be a vent, the part below the tee would be a "waste stack"

    A "waste stack" can not be used for a vent. That means NO.
    You can run a separate "vent" up to the second floor, and tie into the vent at 42" above the 2nd floor.
  6. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    Gotcha. Thanks Terry, your site is very helpful.
  7. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    As I plot my "vent strategy", I have a number of options to consider utilizing the existing vent pipes (to avoid new holes in the roof and a number of other unpleasant options).

    One option is to vent the new toilet up into the main stack ABOVE the entry point of all other fixtures. This itself I know is fine. However, the restriction is that the 4x2 vent tee would essentially be right on top of the 4x4 sanitary tee through which the other fixtures connect. So, there would not be much vertical seperation between the entry point of the vent in the stack, and the entry point of the fixtures in the stack.

    I suspect that some separation is ideally desirable. However, I think this will work fine from a functional standpoint.

    Comments definatley appreciated.

    Cheers.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,686
    Location:
    Cave Creek, Arizona
    vent

    The vent HAS to tie into the main vent at least 42" above the upper floor, not just above the other drain connections.
  9. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    what HJ is saying is that the vent tie in has to be a minimum of at least 6" above the flood rim of the highest fixture draining into that stack... That is where this magic 42" number is coming from....
    You can tie it in in the wall at +42" or higher or in the attic before it exits the roof....
  10. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    Thanks hj and markts30. I figured that would be the answer.

    So, here's my last option for your comments:

    The first floor bathroom is in a 1-storey addition, hence, it has its own roof that is only 1/2 of the total height of the main house. I could give the toilet its own dedicated vent 2" vent through this 1st floor roof.

    The result would be the main stack venting through the main house 2.5 storeys high, and this second new vent venting @ 1 storey high. Is there any problem with terminating outdoors at different elevations?

    Cheers,
    dayster
  11. markts30

    markts30 Commercial Plumber

    Messages:
    630
    Location:
    Phoenix, AZ
    There is not a problem - just make sure the vent is at least 10' away from any openable window or other air intake...
  12. dayster

    dayster New Member

    Messages:
    20
    Location:
    Vancouver, BC
    Thanks to all for the help.

    Happily, I have located an existing 2" vent that i can use! It used to be a drain line, but's been disconnected from that purpose and capped, so I'm good to go now.

    Cheers, Dayster
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