Matt and Steve examine a 2026 ranch home in Climate Zone 6A, focusing on the eave of a high-performance Perfect Wall assembly. They explain how exterior insulation keeps the structural sheathing warm and when interior insulation can also be used without creating condensation risks. The project uses a structural inner wall to simplify header insulation and a two-inch roof ventilation chute suited to cold, snowy conditions. Matt and Steve discuss weather-resistive barriers that resist water, allow vapor drying, and withstand UV exposure. ZIP System® sheathing connects the wall and ceiling air-control layers, while vapor-open materials and vented assemblies support drying around the OSB sheathing. Spray foam at the eave also helps protect air-permeable insulation from wind-washing.