Basement Sink Installation

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by UpTheRiver, Jul 12, 2011.

  1. UpTheRiver

    UpTheRiver New Member

    Messages:
    5
    Location:
    TN
    Hello Everyone.

    I need to install a small sink in our basement. I plan to run the drain into the pipe shown here. The existing soil pipe serves one bathroom with two sinks, one of which gurgles, a toilet, tub, and shower. It does not serve any other areas of the house.

    The sink will be located twenty pipe feet from the CL of the soil pipe against a to-be-built interior wall perpendicular to the concrete wall in the picture. Two 90 degree elbows will be required, one to turn into the interior wall, and one to turn toward the sink.

    I have zero access to the vent stack for the soil pipe in the picture. I do have access to a vent pipe for a different soil pipe serving a bathroom in another part of the basement. However it will be a long run, probably 40 - 50 feet. It will be impossible to maintain a constant slope in the horizontal part of the run.

    For what it's worth AAVs seem to be legal here.

    Comments or recommendations anyone? Any suggestions will be greatly appreciated.
    Thank you for any help you may be able to provide.

    Attached Files:

  2. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    Look above there might be a vent there that is capped off.
    Show a picture where the 3" pvc goes up .
    We might be able to see it.
    Looks like a future rough.
  3. UpTheRiver

    UpTheRiver New Member

    Messages:
    5
    Location:
    TN
    Thanks for the quick reply.

    I'm at another location right now, so no additional pics for several days. I believe I would have noticed any capped off vent lines. though. I looked it over, trying to find one without success.

    It is a future rough, intended for a sink installed right next to the soil pipe. AFAIK, that would not have required a vent. Unfortunately, the situation dictates that it be installed in another location.

    Last edited: Jul 12, 2011
  4. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    You can put an AAV in but you must have access to it when it fails.
  5. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,281
    Location:
    Land of Cheese
    I would look at the floor layout in the main floor, as the most reliable solution would be to run a vent up through an interior wall into the attic, where it can go through the roof or be connected to an existing vent stack within the attic.
  6. UpTheRiver

    UpTheRiver New Member

    Messages:
    5
    Location:
    TN
    There is no way for me to run a new vent pipe to the attic. I can get to an existing vent pipe (different stack) by running a line up in the basement trusses under the main floor. Its a long run, and there is no way for me to have a constant slope. There are just too many obstacles to deal with.

    If a long run is not a problem and a perfect constant slope isn't required, it's doable.
  7. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,281
    Location:
    Land of Cheese
    A horizontal run must be pitched for it's entire length without any question. It cannot have any bends or dips that would allow condensation or drain water to collect at any point in the pipe.

    I have not yet seen a house without an interior wall in which wire or pipe can be run from basement to attic. It does not have to be at the sink.

    Using some patience and careful measuring, up to 2" PVC can fished through a single story 2x4 stud wall without removing any wallboard.
    Lathe and plaster is a little tougher to fish through as the walls are full of rough plaster edges, but houses of that era tend to have balloon framing and real 2"x4" studs, so there is room.
  8. UpTheRiver

    UpTheRiver New Member

    Messages:
    5
    Location:
    TN
    How do you fish the 2" pipe past the fire stops?
  9. cwhyu2

    cwhyu2 Consultant

    Messages:
    1,348
    Location:
    Cincinnati OH
    I want to know the answer to that question.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,267
    Location:
    Cave Creek, Arizona
    An 8' ceiling should not have firestops. That drain may be subjected to both positive and negative pressures since there is a bathroom/toilet above it. An AAV cannot relieve positive pressures. In addition, the vent has to connect close to the sink at the end of that 20' run so it will either be closer or further from that nearest vent.
    Last edited: Jul 13, 2011
  11. UpTheRiver

    UpTheRiver New Member

    Messages:
    5
    Location:
    TN
    The main floor above has a nine foot ceiling. There is a firestop in every wall cavity, without exception. The builder always has his framers install them as they go along in order to help prevent wavy walls. I verified the firestops by looking at pictures I took when the house was being framed.

    While I was going through the pics, I spotted a vent pipe that comes up from the basement floor in a nearby wall cavity. I believe it must be the vent for the floor drain, which is near where the sink is going. I can probably tie the the sink vent to floor drain vent line.

    I had completely forgotten about that particular vent. I think my problem may be solved. Thanks to all who responded.
  12. Obama the Plumber

    Obama the Plumber Plumber

    Messages:
    47
    Location:
    Washington DC
    That's groovy news. Make sure you pull off within 42" for the vent from the trap and you're golden.
  13. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,281
    Location:
    Land of Cheese
    Glad to hear it worked out. I've not yet run into fire stops when installing pipe. My first house was ballon framed, and current one has none either.

    For pulling wire we have long drill bits and long extensions (3' sections) which work great for smaller holes.

    For 2-9/16, I would pull off the drywall and re-do it or make a chase in the corner of a closet.
    Last edited: Jul 14, 2011
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