Best approach to a new 1/2 Bath Addition

Discussion in 'Remodel Forum & Blog' started by VVML, May 3, 2015.

  1. VVML

    VVML New Member

    May 3, 2015
    Hi there,

    I am thinking of adding a half-bath to my house and wanted to get your input on the best approach. The idea is to run the toilet sewer drain (3" PVC) from one end of the house (green square) to the main cast iron drain pipe. I also have to keep in mind that there is also an old 2" cast iron kitchen drain line that currently cuts into the main where I want/need to make my connection. Would it be better to cut off the main and replace it with a PVC wye attached with flexible couplings while trying to connect the kitchen drain somewhere to that new 3" drain or try to find a flexible double wye that can connect both PVC and cast iron and avoiding some of the different material headache in the process (I would likely be able to shift the toilet where it can hook up on the other side of the kitchen drain line)?

    Thank you.

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  2. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington

    You would use a metal wrapped coupling to prevent the pipes from shifting out of alignment.
    But yes, you can cut what is needed to install a fitting for that. It may be easier to cut on the horizontal after the other fitting though.
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  4. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    I think you would want to make sure the cast iron above where you are cutting is well supported before cutting.

    Note that you need slope 1/4 inch per foot. So with 32 ft of horizontal run, you would need 8 inches of drop.
  5. VVML

    VVML New Member

    May 3, 2015
    Thank you, Terry and Reach4!
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