venting question

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Yersmay, Sep 5, 2007.

  1. Yersmay

    Yersmay Writing, constructionDIY Member

    Messages:
    62
    Location:
    Los Angeles
    A kitchen sink will be moved during the course of a remodel and I'm curious about a few things regarding re-establishing a proper vent. There will be a window only six inches above the rim of the sink. But it's my understanding that a vent line must rise at least six inches above the flood rim of an appliance before it can move laterally through a wall. So I'm not sure exactly how to get out from under that window... Somehow I have a memory that a vent can indeed run at a 45 degree angle (or even proceed horizontally with the proper slope as long as its travel is initiated with nothing greater than a 45 degree fitting) even if the vent line has not yet risen above the flood rim. Is this true? Obviously, I'm looking for a way to get that vent out from under the window assembly to a point where it can proceed vertically. I believe it will have to travel about five feet laterally until it is out from under the window. If that travel is initiated with a 45 degree rise, then levels off to a sloped horizontal run, then takes another 45 until it is over the flood rim... then finally takes another 45 degree bend to be truly vertical... does that make it okay? Thanks in advance.
  2. GrumpyPlumber

    GrumpyPlumber Licensed Grump

    Messages:
    1,404
    Location:
    Licensed Grump
    You're correct.
    When I do a kitchen/bath remodel where the existing drain is directly below a new window, I prefer to simply drop a new drain off to the side with a horizontal drain cut in from a T-wye & vent running straight up in the same bay.
    The horizontal drain can then run out at an angle to avoid cutting into studs or window jacks.
    Window jacks are considered load bearing, drilling through them isn't allowed in my state, it could cause a bow in the exterior wall.
  3. Yersmay

    Yersmay Writing, constructionDIY Member

    Messages:
    62
    Location:
    Los Angeles
    Grumpy Plumber,

    At the risk of being the village idiot, here goes:

    I don't need a 'horizontal drain', if I understand you correctly... The drain line can drop straight down into a basement and all will be well. The vent, however, can't go straight up because of the darn window. So if I put a "y" on top of the Santee in the wall and branch that vent out at a 45 degree angle to right under the sub-sill... then (while keeping it sloped) take a more horizontal trajectory until it is past the window, but still below the flood rim.... And because it is still below the flood rim, I will then take the vent upward in another 45 degree angle until it rises above the flood rim... then I can go straight up. Yes, I have to put a big, long header in, spanning wider than all this so I'm not hogging through jacks and king studs. In short... you can take a vent laterally through a wall UNDER THE FLOOD RIM if you use 45's until you're OVER the flood rim and then you're good to go with going straight up.
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