A Cup of Joe: The Air Barrier


In this episode of A Cup of Joe, Dr. Joe Lstiburek walks us through environmental separation, airtightness and the role of air control layers in wall systems (also known as air barriers).

The function of an air barrier is to stop air leakage and resist differences in air pressure by keeping the indoor climate regulated. Essentially, it keeps the outdoor air out and the indoor air in. An air barrier should be:

  • durable enough to withstand construction pressures and handling;
  • impermeable to airflow; and
  • continuous, enclosing or enveloping the entire conditioned space.

High-performing air barriers allow buildings to operate at maximum efficiency day in and day out. They provide peace of mind for installers and tenants who can rest assured knowing that all of the bases have been covered, from cost effectiveness, safety, and comfort to creating a greener footprint. Although the air barrier remains behind the scenes, it can easily be argued that the vital role it plays deserves to take center stage.

DELTA®-VENT SA, a vapor permeable, self-adhering air- and water-resistive barrier, does not require fasteners and comes with BIM models for quick and easy design and application. With the most tightly sealed and secure side laps in the industry, moisture can get out, but not in. This technology helps buildings stay dry and last longer while keeping occupants safe from harmful mold and other problems.


About Dr. Joe Lstiburek 

Dr. Joe Lstiburek is the founding principal of Building Science Corporation, one of the most influential, innovative, and respected building science firms in North America. Dr. Lstiburek’s work ranges widely, from providing expert witness testimony to overseeing research and development projects to writing for the ASHRAE Journal. His commitment to advancing the building industry has had a lasting impact on building codes and practices throughout the world, particularly in the areas of air barriers, vapor barriers, and vented and unvented roof assemblies. His commitment to education earned him the hailing, “the dean of North American building science” by the Wall Street Journal. Dr. Lstiburek holds a Bachelor of Applied Science in Mechanical Engineering, a Master of Engineering in Civil Engineering, and a Doctor of Philosophy (Ph.D.) in Building Science. Get the full scope of Dr. Lstiburek’s work, accolades, and contributions to the industry over at Building Science Corporation.