Vent pipe size thru roof

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by George R, Jul 20, 2006.

  1. George R

    George R New Member

    Joined:
    Mar 7, 2005
    Location:
    Central Illinois
    Adding a new 1/2 bath, just a sink and a toilet. The vent for the sink (1 1/2") and the vent for the toilet (2") will join together in the attic and then exit the roof. These vents are not tied in to any other vents in the house. Can this vent exit the roof as 2" or does it need to be increased to 3" before protruding. No inspection in this town, however, I do want to do it correctly.
     
  2. Dunbar Plumbing

    Dunbar Plumbing Master Plumber

    Joined:
    Apr 18, 2005
    Occupation:
    Service Plumber, Outdoor Temperature Relief Owner
    Location:
    Northern Kentucky/Greater Cincinnati Area
    In Ky, the vent has to increase to 3" 18" before it penetrates the roof and must protrude the roof a minimum of 12".

    The pipe need to extend higher than 12" if the pitch of the roof is steep in my opinion.


    The reason for 3" minimum is to prevent frost-over.
     
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  4. George R

    George R New Member

    Joined:
    Mar 7, 2005
    Location:
    Central Illinois
    Gotcha Rugged, 3" it shall be. Thanks:)
     
  5. hj

    hj Moderator & Master Plumber Staff Member

    Joined:
    Aug 31, 2004
    Occupation:
    Plumber
    Location:
    Cave Creek, Arizona
    vent

    Where do you live? If it is a cold area of the country then you have to increase it to minimize the possibility of hoar frost closing it.
     
  6. George R

    George R New Member

    Joined:
    Mar 7, 2005
    Location:
    Central Illinois
    Central Illinois. It gets cold here.

    HA! Never heard the term hoar frost before. Looked it up on wikipedia, and learned all kinds of new things. Thanks HJ.
     
    Last edited: Jul 21, 2006
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