Shower missing vent, or circuit venting?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by KSC, Jan 23, 2012.

  1. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    I live in a house that's up on pilings, built in 1970, with leaded-in cast iron piping. As part of a bathroom remodel, I would like to move the toilet over a few inches. It's plumbed directly into the main horizontal drain, so it seems like it'd be a major pain to just replace that section. And since the pipes are getting close to 50 years old, probably better to just replace it all with PVC. But if I'm replacing it, I need to do so to code.

    This is the layout, ignoring traps (they are there :) ). I'm not planning on changing the location of the fixtures at all - just moving the toilet over a bit.

    drain plumbing.jpg

    The main drain is 4" pipe, and the main stack is 3".

    The part that concerns me is the shower since it doesn't have a vent of it's own, but I'm not sure if it falls under allowed circuit venting (I admit I don't really understand circuit venting yet, but this layout seems to match that closer than anything else I've found). Or maybe since the shower was a bathtub, they got credit for the tub's overflow? Regardless, it's just going to be a shower now.

    If this layout ok? If not, how can I make it right? I would prefer not to have to run another vent through the roof, if possible. I'm in North Carolina, which is using 2003 IPC with amendments.

    Thanks!
  2. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Last edited by a moderator: Jan 24, 2012
  3. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    I know that, but did the people who installed it, since there's no vent? Or is this a circuit venting and ok? Sorry for bringing up the overflow, don't want to stray off topic. :) Like I said, it's just going to be a shower now anyway.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,641
    Location:
    Cave Creek, Arizona
    That is not circuit venting, and the shower, because of where it connects to the main line is NOT vented. If the kitchen drain pipe is actually installed the way you show it, then it is also NOT vented, in spite of a vertical pipe that you call a vent. The toilet may also be connected with an improper fitting, but we cannot tell which fitting was actually used.
  5. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    Thanks, I suspected the shower wasn't vented. Could I just run a line over to the horizontal section of the main branch to vent the shower? I can draw that up when I get Home tonight if that would help.

    I'm not entirely sure how the kitchen branch is configured, thats just my best educated guess. Why is it not vented in that configuration though? And how should it be?

    The toilet connection will be replaced, so what kind of fitting should it be, to make sure I use the right thing.
  6. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    This is what I was referring to for venting the shower, new pipe in red. Would this work?

    drain plumbing 2.jpg
  7. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    Sorry friend, but that is not gonna cut it.
    A proper vent will rise vertically through a wall that is adjacent to the shower.

    All vent connections must be higher than the wier of the trap, and must rise vertically until they are at least 44" above the level of the floor.

    The kitchen vent must be connected before the drain turns downward.

    If your plumbing is really connected that way, the main vent stack is only cosmetic.
  8. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    Nobody knows how to use the search feature anymore...
  9. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    I'm here to try and learn, folks. Believe me, I've searched. I always search first. But sometimes you don't know what to search for. Sometimes you'd like advice on your exact situation. I appreciate the advice that has been given.

    Ok, makes sense. It's very possible/likely that is actually the case. This is the only section that I cannot readily see.


    dlarrivee, Bert Polk's tips was very useful, thank you. I missed it because the link was added in as an edit, and not a new post. Edit: Looks like Terry added that link in later. Thanks.


    After going through that document and some other posts, here's another drawing of a proposed layout. Sorry it's a little more primitive looking, it's a lot easier to draw lines instead of pipes. I welcome constructive feedback.

    drain plumbing 3.png
    Last edited: Jan 25, 2012
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,641
    Location:
    Cave Creek, Arizona
    NOw you have gone too far. The toilet, if that line ends where you show it, is vented by the lavatory., so you do not need the toilet vent you show.
  11. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    I'm all for less complexity. So the toilet can just connect directly to the main drain trunk with a combination y-1/8 bend and will be vented using the sink's vent as a ??wet vent??

    Does this plan look good?

    drain plumbing 4.png
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,641
    Location:
    Cave Creek, Arizona
    Yes, assuming the right end of the main line is not connected to another bathroom or other fixtures.
  13. KSC

    KSC New Member

    Messages:
    11
    Location:
    Oak Island, NC
    It is not. There would be a cleanout installed at the end of the main line.

    Thanks for all the help!!
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