It’s like a cookie with the filling on the outside. While wandering among the hot tubs and Vita-Mixers at the National Home Show in Toronto, I came upon Philippe Paul and OSBlock, a really interesting structural system invented and manufactured in Quebec. Basically, it is a sandwich of two layers of expanded polystyrene foam with a filling of four layers of Oriented Strand board (OSB) 12″ high by 8′ long. Just stack them up and you have an instant R-32 wall. Want more insulation? Just stick it on the outside. Most importantly, there are no thermal bridges, one of the major sources of heat loss in buildings. It is sort of an inside-out Structural Insulated Panel, with the wood on the inside and the foam on the outside. … The elimination of thermal bridging might make it useful for Passivhaus construction.