PDD Vapor Barrier Location

Answered

Comments

5 comments

  • Avatar
    Scott Barber

    For the exams, you'll always be given a location. There's no universal standards for these types of details that depend on the location, I wouldn't think.

  • Avatar
    Tyler Dallison

    The Vapor Barrier VB is to be on the warm side of insulation. In the first example image, Cold climates the VB goes behind the interior Gypsum and on the interior side of the batt insulation.  In the second example image, Warm climates the VB goes on the exterior sheathing. Think of how a cold glass of water condensates on the exterior on a warm summer day (this is a Warm climate and thus you need a moisture vapor barrier to mitigate water moving thru the assembly.) Images taken from buildingscience.com

  • Avatar
    David Benhamu Esayag

    how about for "hot and cold" climates?

    If you feel this might mean "mixed climates" or "all climates" as AGS breaks it down, welcome to the club. Its a different location depending on whether its one or the other, so I've been unable to know for sure what "hot and cold" climate means, even after looking through specific subject on either BCI or AGS...

     

    anyone? I'd love if ncarb jumped in on this... 

  • Avatar
    Scott Barber

    Since only extreme climates are 'always' hot or cold, most climates are going to experience both hot and cold weather (I'm assuming that's what you mean by "mixed climates"?). You need to place the vapor barrier on the predominantly warm side. I don't remember any questions that were vague about the climate they were asking about, it should be pretty clear if it's a predominantly warm or predominantly cold climate. 

  • Avatar
    David Benhamu Esayag

    You’re so right. But in the are world, they literally called it “hot and cold” climate. I was startled.

Please sign in to leave a comment.

Powered by Zendesk