What are air barrier materials defined as?

Air barrier materials are defined as the "big pieces" of an air barrier assembly because they form the primary components that resist air movement within a building. These materials are crucial in creating a continuous barrier that prevents air leakage, maintaining energy efficiency and indoor air quality. They typically include large sheets, panels, or membranes that are installed in walls, roofs, and foundations to provide a complete air seal.

The correct answer emphasizes the role of these major components in an air barrier system, which is essential for effective air control across various building assemblies. Understanding these materials helps in designing and implementing comprehensive air barrier strategies that meet building performance criteria. In contrast, the other options describe elements that are either too limited in scope or do not fully capture the significance of the materials that constitute air barriers.