On Episode 10 of Build Science™ 401, Matt Risinger and Steve Baczek continue to explore how a home’s exterior envelope must integrate air, water, vapor, and thermal control layers for durability and energy efficiency. Using a 2010 coastal New England passive house as a case study, they examine roof assemblies, insulation placement, ventilation paths, and standing seam metal roofing, emphasizing continuity across transitions and critical details like windows, doors, and double-wall assemblies. They highlight water management strategies, including deep overhangs, vented roofs, and sacrificial insulation layers, and explain how windows uniquely handle all four control layers. Matt and Steve hosts also discuss material choices, air sealing techniques, and raised-heel trusses to maximize thermal performance, showing how careful design, integrated materials, and construction sequencing result in airtight, resilient, and high-performance homes that meet passive house standards.