# Vapor Barriers 101



## KennMacMoragh (Sep 16, 2008)

It's worth pointing out too that there's a difference between air flow and vapor diffusion. Sometimes people confuse the two when saying "Homes don't need to breath". Which is true when speaking in terms of air leaks. But they do need to breath when talking about vapor diffusion. As pointed out in the article, never put a vapor barrier on each side of the wall, that's because you'd suffocate it, vapor would be trapped in there and could accumulate water. Also keep in mind we're talking about standard wood framed walls, the science is a little bit different if you're dealing with ICF's.


----------

