Remodeled Bathroom Venting

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by LarryK57, Jan 18, 2005.

  1. LarryK57

    LarryK57 New Member

    Jan 18, 2005
    I have a 50 year old ranch with 2 full baths (A and B), one of which I have gutted and am remodeling (B). Bath (A) has a 3" copper waste line for the sink, toilet, & tub and vents thru a 3" stack. This same waste line runs about 15 (linear) feet where tub (B) ties in and the whole thing empties into the cast iron main drain. There is a second 3" waste line for the sink and toilet in (B) that is vented by a second 3" stack. This line ties into the cast iron main drain about 4' above the one from (A).

    Originally, the 3" vent in (B) ran thru a closet wall and was at the end of the run. That closet is now gone. I removed all the fixtures and the 3" vent pipe and reconfigured it as follows: I connected a 3" wye (with a 2" branch) to the cast iron main with a rubber clamp-coupling. I will run 3" PVC to tie in the toilet and sink which are 3' apart and 18" from the wye. I replaced the 3" copper vent with 2" PVC coming off the wye and going up thru the attic to the roof. Here is my question: is this enough venting for the sink and toilet or did I make a huge mistake by using only 2" pipe? I figured the other vent was already handling the other fixtures and reducing vent (B) wouldn't really make that much difference. I haven't sealed up the walls yet so I can change it if I need to.

    Please let me know if this is OK. Any/all advice I can get would be greatly appreciated.
  2. Deb

    Deb Plumber

    Sep 5, 2004

    The 2" vent should be adequate to vent the bathroom group.

    However...The sink cannot be connected to the 3" pipe. The pipe between a fixture and its vent is called a trap arm and no fixtures can be connected to a trap arm. Wet venting may be an option. You can install a san tee (for trap arm discharge) on the toilet vent for the lav if your area allows wet venting and you do not exceed trap arm max. The 2" part of the wye that is the vent should be rolled so that the takeoff is above the center line of the 3". It must be graded and you must used drainage fittings.
    The Pipewench
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  4. LarryK57

    LarryK57 New Member

    Jan 18, 2005
    Got it! After reading your reply I realized I need to setup the wet vent for the sink. Not a big deal since the walls are still open. thanks very much for your help.
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