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Community and Q&A

2″ plumbing vent to daylight

bradrea | Posted in Building Code Questions on

In order to avoid roof penetrations in CZ  4 (marine) , is it ever permitted for a 2″ plumbing vent to daylight through an attic sidewall and then transition to a vertical  orientation outside of the eve drip-line?

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  1. Mark_Nagel | | #1


    I am in no way an expert on this, but my understanding is that the primary concern is that any horizontal runs have a slope in them to allow water/moisture drainage downward (to meet up with the proper wet drain portions). Seems like there is some minimum elevation above exit points, but I am, at this time, unaware of whether there are any and what they might be.

    I know that there are concerns with/over/for icing situations in colder climates, but this is unlikely going to be an issue in your climate (which is the same as mine).

  2. Expert Member
    NICK KEENAN | | #2

    Check your local code, but it shouldn't be a problem. It still has to extend above the roof, and you might have to take extra steps to keep it from freezing in winter because so much of it is exposed.

    My local code requires only one roof vent for the whole system, the rest of the venting can be accomplished with air admittance valves.

  3. Patrick_OSullivan | | #3

    It's quite possible to properly flash a vent pipe through a roof and to do so in a way that will be less aesthetically objectionable than a pipe that comes out a side wall and then goes up.

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