Protecting a structure against air intrusion

Role of an air barrier

Air barriers have a singular purpose: keep outdoor air out, and indoor air in. Simple to say, but not as simple to do. Air barrier systems should be:

• Impermeable to air flow.
• Continuous over the entire building enclosure or continuous over the enclosure of any given unit.
• Able to withstand the forces which may act on them during
  or after construction.
• Durable over the expected lifetime of the building.¹

Note

¹ Consult BSD 104: Understanding Air Barriers by Joseph Lstiburek, Building Science Corporation, Oct. 24, 2006. https://www.buildingscience.com/ documents/digests/bsd-104-understanding-air-barriers.