Equally important as correct material selection, proper installation is critical in order for an air barrier system to work as intended. Even when the primary air-barrier material meets ASTM requirements, system continuity can still be compromised by incompatible tapes and flashing or improper installation. (This is just one of several reasons why construction details and pre-installation meetings are so important.)
Sealing all laps and penetrations with the proper tape can improve the building wrap’s performance by 20 percent. Horizontal laps are just as important as vertical laps because windblown rain can travel sideways or even up and over an improperly installed lap. Any tears and holes should be sealed with manufacturer-recommended tapes, and all windows and doors should be properly flashed. The goal should be to create a continuous building envelope free from any penetrations through which air could potentially pass.
During installation, it is also important the proper nailing pattern be followed to ensure the material is kept against the wall and not blown off. Galvanized roofing nails or plastic cap nails should be used to attach the air-barrier material to the structural sheathing and framing. Uncapped nails, staples, or screws can contribute to tearing and moisture intrusion—they must not be overlooked.
The simplest way to ensure the entire system works together effectively and meets all code requirements is to specify wrap, tapes, and flashing from a single manufacturer. Doing so provides added assurance each component comes together seamlessly; further, the system will be covered by the manufacturer’s warranty.
The use of air barriers in commercial construction is growing, driven by advances in building codes and increased awareness of their ability to support sustainable, comfortable buildings. However, not all air barriers are equal in performance or design, and there is not one solution suitable for all climates, regions, and project conditions.
Understanding how air-barrier materials and systems are evaluated, and knowing their performance characteristics, helps design professionals find the right solution for their project needs. Approaching air barriers from a holistic view and evaluating the entire system—rather than just an individual material—results in a tighter and far more durable enclosure that can stand the test of time.
Bijan Mansouri is the technical manager at Typar Construction Products. He has been with Berry Plastics for the past 25 years, working in different technical capacities. Mansouri is responsible for building code requirements, design and development of new construction products, and education on proper practice and installation of building envelope. He received his bachelor’s and master’s degrees in mechanical/aerospace engineering, and is a member of the Air Barrier Association (ABAA) and ASTM. He can be reached at email@example.com.