Radiant barrier insulation
mikeysp| Posted inGeneral Questionson
Zone 4a
I understand that radiant barrier insulation is much hype. However, why would it not work as an air barrier on a post frame assembly? Obviously it would not dry to the exterior, but it would still dry to the interior.
I ask because I have access to several large rolls for next to nothing and I am trying to save pennies without creating a nightmare later.
Thank you for your comments.
-Mike
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Mike,
Where in your assemblies are you proposing using the radiant barrier, and what do you want it to replace? Were you planning to use another sheet good as the primary air-barrier?
Malcolm, I was thinking on the girts. I am basing my construction on materials I am able to find for pennies on the dollar. I came across these rolls for very little, so I thought about the utility of using it. Turns out it is perforated, so it will not serve as an air barrier anyways. I will probably end up using 2x with osb air sealed and polyiso with a rain screen at this point. I have a bunch of 2" polyiso.
If the radiant barrier you have is the usual stuff (non-perforated), it will behave pretty much like a sheet of polyethylene. This means the radiant barrier will have all of the problems and all of the advantages (depending on what you’re trying to do) that poly would have if used in the same place.
Bill
Bill, turns out it is perforated. It is thin stuff also. I am thinking I will pass on this deal.
You may be able to use it in your attic under the rafters. I’m not sure if it would offer enough benefit to be worth the effort though.
Bill