One inch of Closed-cell spray foam insulation is an approved vapor barrier with permeability being at, or below most asphalt and rubber based waterproofing membranes on the market. Closed-cell foam is approved for exterior and sub-grade applications.

Whether you are building a new structure or gutting and renovating an existing home/building I think that getting the best insulation for your buck is going to come up at some point.

Code officials should understand the difference between the air-tightness of a home and the conductive values eliminated by insulation. Test the theories and re-write the codes.

Whether or not you decide to read the article that my comment below is posted on (http://houseblog.ottopohl.com/2010/02/05/foaming-about-insulation/comment-page-1/#comment-41). I think you will find my information informative and revealing.
–Wow!!!
You did your research! I am very impressed that you were able to calculate all of those figures and actually obtain some of the “secret” information that you did.
I [...]

Forty percent, Yes 40%, of heat loss or gain in homes without spray foam insulation is due to excessive air-leakage. The only insulation product that creates a +99% air-seal is spray foam.