Adding vent line for basement bathroom

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by zspinner, Mar 30, 2012.

  1. zspinner

    zspinner New Member

    Messages:
    1
    Location:
    CT
    Hi, I am installing a full bath in my basement and I am working on picking up a vent line from a 1st floor bathroom sink. I need to run the new vent line approx. 20 feet to where the 1st floor sink is. This also requires 4 direction changes (90 deg bends) to get from the new bath location up to the floor joist in the basement ceiling and then around pipes and other obstructions in the floor joists (through 5 joist spans) before I get to the existing sink vent location. Are there any restrictions on direction changes in vent lines before I tie into the existing 1-1/2"? Thanks.
  2. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    There are restrictions, the primary being that the pipe must have pitch to drain in any horizontal run, and cannot have any "jogs" in the line that would prevent complete gravity draining. Some areas also have limit to the length of any horizontal section to a percentage of the overall length of the vent. While there might not be a restriction to the number of bends, there should be one accessible cleanout in the line for every 135 degrees of change in direction.

    You should also consider that the 1-1/2" vent allows no room for expansion. If you wanted to add the laundry or another sink in the basement, you would need to run another vent through the roof.

    It is always best to locate a place in the house where you can go straight up from the basement through the roof. As an alternative, you can run straight up into the attic and connect to an existing vent there. Where there are no stacked walls to run a vent through, there often are stacked closet spaces where a vent can be run in a corner of a closet and boxed in after the plumbing inspection is completed.
  3. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,142
    Location:
    South*East
    You do realize that the vent must tie in above 6" above the flood rim of the sink on the first floor.

    John
  4. kreemoweet

    kreemoweet New Member

    Messages:
    371
    Location:
    Seattle. WA
    You say "full bath", so I guess there is a toilet being vented, but a toilet requires a minimum vent size of 2".
    Your 1 1/2" vent won't fly.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,472
    Location:
    Cave Creek, Arizona
    There are NO vent lines in the basement that you can tie your vent to. Unless you already have a sink or something down there which is vented, but in that case it would probably be 1 1/2" instead of the 2 you need.
  6. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,244
    Location:
    Land of Cheese
    The OP falls under the IPC, under which an entire bath group can be vented through a 1-1/2" stack.

    I was under the impression he was planning to connect the minimum distance above the flood rim of the existing sink, but that might be a bad assumption on my part.
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,124
    Location:
    Maine
    Correction my friend. Two entire bath groups can be vented through an 1-1/2" line under the IPC
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