Another venting question

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by TDVT, Dec 10, 2009.

  1. TDVT

    TDVT New Member

    Messages:
    10
    Location:
    Vermont
    Hi, We are preparing for an upstairs bath renovation in a 1 ½ story timber-frame house. Each floor will have 1 full bath with the kitchen also on the first floor & the washer in the basement. The house was owner-built in the 80’s & there are a few un-vented fixtures & I would like to correct any faults during the renovation process.

    My question is regarding venting. It is not clear to me if is it required to maintain a constant stack all the way from the sewer to the roof (3†in this case) or can I treat the two floors separately (10 fixture units 1st floor, 6 fixture units 2nd floor) venting each floor with 2â€, then joining the two into a 3†vent in the attic for the roof penetration ? The timber frame of the house makes pipe runs even more difficult so the smaller diameter would make things quite a bit easier & minimize any boxing in that is likely to come up.

    Thanks, TD
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    [​IMG]

    In most codes, you need to have a composite area of 3" going up.
    If your kitchen goes up separately, you would count that area, and the area for the washer if it goes up on it's own.
    In the drawing above, I have two bathrooms vented with 2"
  3. TDVT

    TDVT New Member

    Messages:
    10
    Location:
    Vermont
    Hi Terry, Thanks for your reply. If I am able to vent this way, I would have the kitchen sink, washer & one full bath on one 2" vent straight to the attic & then one full bath also straight to the attic (separate run) & they would then join at the existing 3" roof vent.

    I saw that very drawing in another thread which is what got me wondering. Thanks for a great site.

    Best, TD
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,416
    Location:
    Bothell, Washington
    In that case, it takes two 2" lines and one 1.5" to make a composite area of a 3" pipe.

    2- 2"
    1- 1.5"
  5. TDVT

    TDVT New Member

    Messages:
    10
    Location:
    Vermont
    Thanks, There is enough room in the chase to run another 1 1/2" or 2" vent all the way from the washer (bsmt) to the attic. Sounds like that will work!

    Thanks again, TD
  6. DVMSteve

    DVMSteve New Member

    Messages:
    44
    Location:
    Jones County, NC
    I did my log home similarly, and it works extremely well, and the inspector was fine with it. I had the same problems with pipe runs: none in exterior walls, or interior log walls.
  7. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,251
    Location:
    Cave Creek, Arizona
    vents

    As long as you already have a 3" vent out the roof, you could join all the basement plumbing into one 2" vent which would extend up to the attic, and then either connect to the 3" vent, or penetrate the roof separately.
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