Please Critique Basement Bathroom Drain Rough Plumbing Plan

Discussion in 'Plumbing Code Questions' started by rcalliott, Feb 18, 2021.

  1. rcalliott

    rcalliott New Member

    Joined:
    Feb 18, 2021
    Location:
    St. Louis, MO
    Looking for feedback on my planned drain rough ins before I start busting concrete to build a basement bathroom with a sink, toilet, tub/shower combo.

    IMG_4901.jpg

    Blue tape represents existing 4" PVC drain pipe under slab.

    PVC Fittings from left to right:
    • AAV (in the box) atop 2 inch tee serving the sink drain (will be recessed behind the drywall in the vanity).
    • Next is a 2" long sweep 90 degree turn from vertical to horizontal.
    • Then a 2" 45 degree fitting to get the pipe slotted into the 3x3x2x2 Double Wye.
    • Double Wye serves toilet above it via 3" pipe, and connects to 4x4x3 45 degree wye attached to existing 4" pipe 12" to 15" under the slab.
    • Fernco fittings with PVC stubs to attach wye to existing drain pipe, which flows from left to right in the picture.
    • From the right of the Double Wye is a 2" pipe with various 45 degree fittings to get the angle correct to the 2" p trap for the tub/shower combo (furthest item on the top-right).

    With a wet vent from the sink, my understanding of the toilet NOT being the last fixture on the pipe requires the Double Wye/Symmetric Fitting.

    Seems like some folks don't care for the AAV. on the other side of the top wall is my workshop with access to the main stack and a vent that goes up through the roof. If the AAV functions poorly in this configuration, I can tap into this 1.5" vent pipe...its just a pain I'd like to avoid.

    Any feedback and general comments/suggestions are appreciated.
     
  2. Sylvan

    Sylvan Still learning

    Joined:
    Sep 23, 2004
    Occupation:
    plumbing - fire suppression - boiler inspector
    Location:
    New York
    GET rid of the fernco coupling. Go with shielded couplings

    [​IMG]
     
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  4. rcalliott

    rcalliott New Member

    Joined:
    Feb 18, 2021
    Location:
    St. Louis, MO
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