"Over the last year I've really been working on how to get my houses to the next level of greater energy efficiency and this video will show you my latest secret. We're laying down a thick layer of rigid ISO foam boards on top of the roof . We are using 1.5" of foam bonded to 1/2" OSB decking. This will make a continuous blanket of R9.6 insulation on top of the roof plus the 5.5" of open cell spray foam inside on the underside of the roof for a total foam R value of R28.6. I really like that this foam on the roof will span over our 2x6 roof rafters and eliminate thermal bridging at the wood rafters. This turns our conventionally framed house into a sort of SIPS hybrid. I also want to mention that our roof is a highly reflective silver "Galvalume" standing seam metal roof that acts as a radiant barrier. I foresee very low cooling bills for this little farmhouse! -Matt Risinge"