Matt and Steve explore a 2021 modern Passive House in coastal Climate Zone 5A, built using a prescriptive Passive House approach. The roof incorporates a clear-span truss system that creates an HVAC plenum above the ceiling for ductwork and mechanical equipment. They examine how ZIP System® sheathing contains the substantial cellulose insulation while establishing an airtight boundary. They trace the primary air-control layer and explain how closed-cell spray foam at the eaves connects the roof and wall assemblies. The episode also covers rainscreen detailing for vertical siding and the exterior wall’s vapor profile. Matt and Steve emphasize that successful high-performance construction requires careful coordination of mechanical systems, insulation, airtightness, and drying potential.