venting main floor lavatory

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by t-roy, Feb 28, 2005.

  1. t-roy

    t-roy New Member

    Feb 28, 2005
    I am adding a bathroom to my basement directly below the main floor bathroom. The main floor bathroom lavatory was setup to have a P trap, and then a two foot horizontal pipe into a 2" vent/drain pipe. That drain pipe went down through the floor, and then horizontally into the main cast iron stack. The problem is the previous owner set the horizonatl pipe below the floor, to be at a height of about five feet off the basement floor. This pipe is now in the way of my new bathroom.

    I redirected the drain of this main floor lavatory to have an "S" trap, and then to go straight down through the floor, and then directly into the cast iron vent stack that it previously entered, (and at the same spot in the cast iron vent stack). So, the difference now is that the lavatory drain doesn't make the 2 foor horizontal into the vent/drain pipe.

    My question is whether or not the main floor lavatory is now correctly vented. The diagram attached shows the new drain layout. The main floor lavatory is less than 3 feet measured horizontally, from the main cast iron stack.

    Attached Files:

    Last edited: Feb 28, 2005
  2. Plumber2000

    Plumber2000 Plumber

    Jan 13, 2005
    Eugene, Oregon
    S-trap are illegal under all codes.

    You can't do it like that.

    You need to vent it before the tie in or unless the stack is with-in 3'6" then you can use the stack for the vent.

    See how tub connects to the vent, same way with the lav and you will be set.
    Last edited: Mar 3, 2005
  3. Sponsor

    Sponsor Paid Advertisement

Similar Threads: venting main
Forum Title Date
Plumbing Forum, Professional & DIY Advice Venting new main floor bath.. will this work?? Jan 31, 2014
Plumbing Forum, Professional & DIY Advice Basement Ejector Pit Venting Main Stack Mar 7, 2011
Plumbing Forum, Professional & DIY Advice IPC Code: Main line and Venting size Dec 5, 2007
Plumbing Forum, Professional & DIY Advice Need advice on DWV venting Sunday at 12:19 PM
Plumbing Forum, Professional & DIY Advice Yet another question about wet venting. Apr 20, 2017

Share This Page