Following up on our earlier post celebrating our most recent award-winning project, Harvey and Kay’s “Pleasant Future Vision” PHIUS+ Zero certified passive house home, we continue to take you behind the scenes revealing some of the high performance assemblies employed on this amazing project. Bringing the building envelope exploration up to the roof we are going to be looking at what we call “the lid”. It is said that a high-performance home needs, “a good hat and a good pair of boots”. The continuity of the air control layer (second only to the water control layer in importance of the four key control layers of the home) is critically important at the ceiling plane for two reasons: warm air is more buoyant than cool air, and humid air is more buoyant than dry air… Everything is heading to the top of the home. Having a complete, continuous, uninterrupted air control layer is critical to preventing warm, moisture-laden air from entering the vented attic space and potentially condensing causing mold, mildew and decay. This is particularly important in the situation where we have attic insulation generating an R-110 where very little energy flux will be moving through the assembly, reducing its drying potential. In this home we used a two-layer “lid”, allowing penetrations in the lower plane, a service cavity, and an air-tight upper plane. Learn more here: https://bit.ly/4hPxeOv