Include air, vapor, and thermal control layers to provide Passive House levels of energy efficiency, comfort and durability.

Today, we have access to materials that provide a robustness previously unavailable to the industry.

Airtightness maximizes the effectiveness of the insulation and optimizes occupant comfort. The insulation should be surrounded by airtight layers with a continuous inboard and outboard air barrier. The inboard air barrier should be a smart vapor retarder. In heating dominated climates, the outboard air barrier should be vapor-open.

Smart vapor control ensures that highly insulated assemblies, which tend to stay wetter longer, have maximum drying potential over the course of the seasons. Consequently, the insulation is drier, and drier insulation is better at insulating. Wood, wool, and cellulose insulations help buffer moisture levels.

Thermal control is fundamental to comfort and energy efficiency. It must be continuous. Where the insulation is discontinuous, thermal bridges result, causing discomfort, inefficiency, condensation, and ultimately, moisture damage.