Round 3: Double Vapor Barrier Battle!

In case you missed it, here are the previous two rounds:

Round 1: Green Building Advisor Sounds Off! (may need a paid subscription to view this page)

Round 2: 475 High Performance Building Supply Answers Back!

Now we've (unofficially) entered Round 3: Building Science Corporation Enters the Ring. Unofficial because BSC doesn't directly address the previous two posters. The timing of their publishing the article, however, and the fact that they were directly cited by the original Green Building Advisor article (referencing BSC founder Joe Lstiburek) suggest this piece is intended to be a contribution to the discussion.

So who won the debate? Well, the rest of us did: all of us designers, builders and green building advocates. We now have a rich discussion citing several scientific studies and years of field observations on the oft-misunderstood topic of controlling water vapor using some of the newest, "smart" products available.