GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. plumb_bob | | #1

    The vents need to 1) achieve air movement while 2) keeping out the weather and critters.

    1) is possible through a variety of means
    2) is most practical by venting out the bottom of the rafters, at both the high and low sides of the roof.

    Standard detail is to have ventilated soffits at both ends of the rafters. If the vent channel is sized properly then this system will work. As long as the air has an unobstructed path in and out of the vent channel you will be in good shape.

    1. Deleted | | #3

      Deleted

  2. Expert Member
    MALCOLM TAYLOR | | #2

    Casey,

    Looking at it solely from the perspective of efficient air-movement, and not leaving any dead-ends that might accumulate moist air, the two options closest to the peak are the best - and venting up into the ridge flashing wins out. However situating a vent-opening on the roof surface opens you up to potential bulk water intrusion in windy conditions, so I would opt for venting through the soffit close to the fascia.

    Honestly though, I'm not sure it matters all that much. I've seen all three done successfully.

    1. Deleted | | #4

      Deleted

      1. Expert Member
        MALCOLM TAYLOR | | #7

        Casey,

        I agree with plumb_bob.

  3. plumb_bob | | #5

    I would GUESS that under windy conditions there will be pressure differentials created that will interrupt the normal flow of air through the rafter vent channels, but this is just intermittent, and the regular flow from bottom to top will be the prevailing flow.
    The detailing of the ceiling air barrier will be a much bigger factor in the success of this roof than the vent location.

    1. Deleted | | #6

      Deleted

      1. Expert Member
        MALCOLM TAYLOR | | #8

        Casey,

        Is that your account which has spent the afternoon spamming the site with AI generated responses?

        1. Expert Member
          MALCOLM TAYLOR | | #9

          Casey Koontz of Proper Built in Oregon. Can you confirm you aren't posting all these responses?

          1. Expert Member
            MALCOLM TAYLOR | | #10

            Bump

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |