Dense-Packed Cellulose and a Wrong-Side Vapor Barrier
I'm not actually that surprised that Hulstrunk's wall works. I've seen cellulose defy some very steep odds and have attributed this to it's hygroscopic properties. That said, the biggest problem with this assembly is that it probably depends largely on the perfection (.09ACH50) of the building envelope, the interior air barrier to be exact. Putting this assembly into production (which I assume should be the goal of any wall assembly) would be to subject it to inevitable errors, even with a blower door tests things happen, or down the road a homeowner put an accidental chink in the interior armor. Where as say Chris Corson's walls (vapor open) could put up with some moisture intrusion, Hulstrunk's wall seems like it would have serious problems in short order, especially with elevated indoor humidity (occupant behavior). Please correct me if I'm wrong.