Vent Stack Iregularities

Discussion in 'Plumbing Code Questions' started by Robin11, Apr 16, 2020.

  1. Robin11

    Robin11 New Member

    Joined:
    Apr 16, 2020
    Location:
    Maryland
    I discovered that it appears that my vent stack was completely disconnected above the attic. I'm not sure what to do about it. I discovered this as a result of water damage, after poking around above the fiberglass insulation. I had assumed that it was due to a leaky roof in previous repairs(the second time), but now I am inclined to think it is the vent stack, which doesn't appear to have a cap, as the disconnect is directly above the water damage, and in the attic the water wouldn't have had to run very far.

    What is the proper way to connect the pipes. PVC glue? Also, I have sneaking suspicion that the same workmanship may be found elsewhere, as there is another subtle leak above my kitchen, which I haven't been able to track down. Is there any harm in putting a cap or elbow on the vent stack? If I haven't noticed any other problems, eg smells is there any harm in letting it sleep after that?
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    PVC glue works if the pipe is PVC. You can also use shielded (banded) couplers.
    Elbow can be in the path, but there should be a downward slope of 1/4 inch per foot or more in the horizontal sections.

    The vent through the roof usually does not have a cap. That little bit of rain that lands right over the pipe will go down the drain.

    The pipe through the roof needs vent flashing /boot. It will be plastic or lead. The best is lead. That should be a special shingle that gets mixed in with your other shingles if you have shingles. A roofer can tie those in readily.

    Protect PVC through the roof from direct sunlight with the flashing or paint.
     
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  4. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    It probably there is an unglued coupler for the last section of vent pipe to the roof. During the roof repair the boot for the vent pipe may have been removed and replaced and subsequently the pipe was pulled on and it disconnected at the coupling.
     
  5. Terry

    Terry Administrator Staff Member

    Joined:
    Aug 17, 2004
    Occupation:
    Plumber
    Location:
    Bothell, Washington
    You don't want to cap vents in the attic. Those are meant to go through the roof to disperse the sewer gases into the jet stream flowing past your home. You really don't want that hanging around in your attic.
    And the venting needs to be functional to prevent traps siphoning in the home.
     
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