How Do Air Barrier Systems Affect Building Performance?

All buildings require air barrier systems.

There are three very important reasons to control the airflow inside of a building:

1) Moisture Control. No one wants water damage due to water vapor condensation, or mold growth encouraged by wet walls.

2) Energy efficiency. An air barrier can reduce cold drafts or humidity fluctuations, and keep the indoor temperature regulated simply by preventing conditioned air from leaking out of a building and unconditioned air from leaking in.

3) Comfort. Besides temperature and moisture regulation, air barriers are also responsible for blocking out sounds and smells from the outside world.

A good air barrier can ensure good air quality, reduce cold drafts or humidity issues, reduce the condensation of water vapor, control the indoor temperature, and cut down on sounds and smells from the outside world.

Two main types of air barriers are, fluid-applied monolithic membranes and self-adhered barriers. In a recent showcase in D+D Magazine, John Chamberlin of Sto Corp and Peter Barrett of Dörken Products agreed that the difference between the two types, provided that both meet industry standards, is in the details rather than the fundamentals. It’s not as simple as just choosing one type and slapping it on, though—both fluid-applied and self-adhered barriers usually come in a packaged system by the manufacturer, with different types of the product being used in different climate situations or on different areas of the building.

The main takeaway, though, is this: neither type of air barrier can guarantee results if it is applied improperly. Therefore, choosing a product should be secondary to making sure it is installed according to guidelines. Air barriers work by creating a continuous system; any disruptions can force another part of the building to act as an ‘air barrier,’ often leading to disastrous consequences.