No announcement yet.

Venting solution for bathroom remodel

  • Filter
  • Time
  • Show
Clear All
new posts

  • Venting solution for bathroom remodel

    Attaching a couple of photos for background ...had the rough work done and not happy with it, but am where I am.

    House is two story with finished basement ...lot slopes away so septic tank and field all below grade of the basement bathroom - no septic pump. House has two main vent perforations of the roof. The one I am working with is 3". As you can see from the photo, it needs to be removed

    The new toilet and shower flow to the same horizontal waste pipe in a shared pipe. The tub and vanity sinks via another line to the same horizontal waste pipe higher than the toilet/shower.

    Flooring, shower base, etc all in now, so can't change anything without ugly consequences.

    The main bathroom stack (serviced bathroom - connected down to horizontal waste pipe and up to vent through roof), was removed and temporarily terminated at ceiling level (see photo in attic) in prep for complete removal, prior to using AAVs on all the remaining vents (1. A single 2" from somewhere from first floor, 2. A 2" three-into-one from somewhere downstairs/adjacent bathroom, and 3. The new 1 1/2" vent services the toilet and shower (see photo)).

    I have attached a very rough drawing of what seems like what should be done if I want to avoid AAVs ...since I don't know where vents 1. and 2. go, is it reasonable to use vent 3. as the vertical "stack," transition it to 2" and then connect 1. and 2. to it in the attic, removing the existing 3" and staying with 2" through the roof in a new cap?
    Attached Files

  • #2
    Re: Venting solution for bathroom remodel

    AAV's are useless - they wont let air out, only in. venting needs both.

    in pic #2, i hope they used ABS to PVC transition glue. Else, you will have leakage problems in the future.

    I'm not understanding why the 3" stack needs to be removed? I seem to recall in the code that the vent size only need be 1/2 the given diameter of the largest drain in the house (it's a rough sizing based on dfu's and developed length but in most household applications it should hold true) (someone clarify if i'm incorrect). Why can you tie 2" into the existing 2" vent from the first floor?

    916.1 Size of stack vents and vent stacks. The minimum
    required diameter of stack vents and vent stacks shall be determined
    from the developed length and the total of drainage fixture
    units connected thereto in accordance with Table 916.1,
    but in no case shall the diameter be less than one-half the diameter
    of the drain served or less than 11/ 4 inches (32 mm).
    Last edited by Plumber Punky; 11-29-2013, 11:58 AM.

    ... it was plumbed by Ray Charles and his helper Stevie Wonder


    • #3
      Re: Venting solution for bathroom remodel

      Plumber Punky,

      The existing 3" stack is terminated just below the insulation ...can't see it from photo just fills up with water ...I suppose I could cut everything off under the last piece of 3" pipe and transition from 2" there ....?

      Did you mean in last sentence of your reply, "Why can't you ...?"