Air Barrier – Defined
Material(s) assembled and joined together to provide a barrier to air leakage through the building envelope. An air barrier may be a single material or combination of materials. (Continuous Air Barrier – A combination of materials and assemblies that restrict or prevent the passage of air through the building thermal envelope.)
WHAT IS AN AIR BARRIER?
The ceilings, walls, and floor/foundation that separate the inside conditioned space from the outside or unconditioned space form the air barrier and the insulation barrier for a house. These two barriers differ by the materials used.
For most homes, the sheet goods that form the ceilings, walls, and floor (such as drywall, sheathing, and decking) are effective at stopping air leakage. It is critical to seal all holes and seams between these sheet goods with durable caulks, gaskets, and foam sealants to create a continuous air barrier. The insulation barrier is usually made up of standard insulating materials, such as batt or loose fill products, that do not seal against air leakage.