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Thread: Ridge Vent.

  1. #1
    Join Date
    Mar 2007
    Location
    Daniel Island, SC.
    Posts
    240

    Default Ridge Vent.

    Inspected a house today that had a ridge vent properly installed but the plywood cut underneath the ridge vent varied from 1/4" inch in someplaces to 2" inches on each side of the ridge board. What is the standard or the code for such an opening?

    Thanks, Jim

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  2. #2
    Jon Randolph's Avatar
    Jon Randolph Guest

    Default Re: Ridge Vent.

    There should be about 1-1/2" gap between the decking at the ridge. There also needs to be additional venting (preferrably a continuous soffit vent on each side) for a ridge vent to work.

    I call out most attics for needing to improve venting. The only way to effectively ventilate an attic using a passive venting system is a properly installed continuous ridge vent in combination with continuous, unblocked, soffit vents.


  3. #3
    Join Date
    Mar 2007
    Location
    Daniel Island, SC.
    Posts
    240

    Default Re: Ridge Vent.

    Thanks Jon,

    There was a soffit vent but as stated earlier, the gap was all over the place. Less than an 1/2" in places and wider in others. I recommended a roof fan controled by a temperature gauge or humidistat.


  4. #4
    Jon Randolph's Avatar
    Jon Randolph Guest

    Default Re: Ridge Vent.

    I just recommend improvement and let them know what I consider to be the best combination. How/if they improvement is up to them. There is some evidence that powered fans are not that effective either. The fan will be installed at a gable vent according to the instructions, but in reality it will pull air in trough the nearest opening (ridge vent) and blow it out of the gable - bypassing the rest of the attic.


  5. #5
    David Banks's Avatar
    David Banks Guest

    Default Re: Ridge Vent.

    Cor a Vent says 1 1/2 on each side of ridge. Think this is typical.
    http://www.cor-a-vent.com/pdf/4pg-install.pdf


  6. #6
    Join Date
    Mar 2007
    Location
    Plano, Texas
    Posts
    4,245

    Default Re: Ridge Vent.

    I recommended a roof fan controlled by a temperature gauge or humidistat.
    Jim, this is from another Jim , I have found power ventilators to be about the worst possible ventilation product out there in my research and personal experience. You may live in a totally different climate that would change my thinking, but around here there are just too many draw backs.
    Short life, high energy cost, and drawing conditioned air out of the house are just a few. I don't think I have ever seen one still alive after more than 5 years, typically they are toast after 3 years.
    Just me, but I would not recommend installing a power ventilator in an attic unless it was the last possible alternative... and maybe not even then.
    JMHO - the other Jim

    Jim Luttrall
    www.MrInspector.net
    Plano, Texas

  7. #7
    Join Date
    Aug 2009
    Location
    Michigan
    Posts
    249

    Default Re: Ridge Vent.

    Quote Originally Posted by David Banks View Post
    Cor a Vent says 1 1/2 on each side of ridge. Think this is typical.
    http://www.cor-a-vent.com/pdf/4pg-install.pdf
    We always try to get 2" from the center of the ridge. Otherwise with a 2x ridge board you only get an effective 3/4" air gap on each side. Never been a problem with fastening or leaking. An extra 1/2" along the entire ridge, on each side, surprisingly makes a big difference with ventilation.

    Randy Gordon, construction
    Michigan Building Inspector/Plan Reviewer

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