Tee PVC into Cast Iron Drain

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jmengel, Dec 1, 2008.

  1. jmengel

    jmengel New Member

    Messages:
    4
    Putting in a new bathroom upstairs and are running a new 3" PVC stack down to meet with the main drain line in the basement. Rest of the house is hubbed cast iron. Have dug through the basement slab and am about to snap the 4" cast iron and T the PVC into the main waste line. My plan is to use a 4x4x3 PVC Wye and glue a few inches of 4" PVC into the 4" ends of the wye and use shielded hubless neoprene boots to connect the 4" PVC stubs to the cut ends of the 4" cast iron pipe. Is there a fitting designed for this or is this the best way to T a new PVC system into an old cast iron system? Seems like a kludge to me, there must be a better way.

    Additionally, is it preferred to dig out an entire hubbed length of the cast iron or is it OK to just snap cut out a small (18") section and replace with a PVC T as described?

    Thanks for your help!

    -Jon
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    If you are cutting into the cast stack, use a cast tee.

    Once the tee is in place, you can run off of it with PVC
  3. jmengel

    jmengel New Member

    Messages:
    4
    I am cutting into the horizontal run under the slab. Is a cast hubless Tee still preferred in this application?

    -Jon
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    Horizontal? You could go either way,
    I like using the no-hub cast wyes though.
    It's closer to the pipe size and looks a bit cleaner.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    connection

    It also takes less pipe removal to get it in.
  6. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Make sure you tee in in ten pipe diameters from any branch.
  7. jmengel

    jmengel New Member

    Messages:
    4
    Thanks for all the tips everyone. This site has been an important resource for my whole plumbing project.

    -Jon
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