Not only do air barriers help protect buildings against devastating moisture issues, they dramatically improve energy efficiency by reducing air infiltration and exfiltration. Today’s air barriers are sophisticated materials with advanced properties to protect the building from water, air and sometimes vapor transfer. These products are developed by scientists and are tested in labs under ideal conditions. But buildings aren’t built in labs or by scientists and are often constructed in less than ideal conditions.
The truth is, air barriers are only as good as the substrate, and the substrate is almost always constructed by a different trade. Further complications for air barrier installation include weather, construction sequencing and adjacent materials coordination. This article will discuss the proper construction of the substrate and common pitfalls during air barrier installation in the field.