A Guide to Air Barrier Installation

Codewatcher air sealing guide Typar

Establishing a continuous air barrier can make a big difference in the performance of a house.

As building codes continue to advance, it’s key to stay fresh on proper installation techniques. Here are some tips to follow in order to speed up your installation and keep the building inspector off your back.

Why Use An Air Barrier?

It is important to establish a continuous air barrier for several reasons. As an air barrier isolates the indoor environment, it plays a major role in the overall energy efficiency, comfort, and indoor air quality (IAQ) of a building. According to the U.S. Department of Energy (DOE), up to 40 percent of the energy used to heat and cool a building is consumed due to uncontrolled air leakage. Establishing a continuous air barrier reduces heating and cooling costs, thereby lowering greenhouse gas (GHG) production.

Numerous materials can achieve the ASTM air leakage requirement, but this does not
necessarily mean they will perform in the field once installed as part of a system. The question
becomes whether the material will be able to hold up to the rigors of the jobsite and if system
installation is done correctly. After all, an air barrier’s performance is defined by its weakest
link, and it only takes one tear or unsealed connection to compromise the entire system’s
integrity.

Proper Installation

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 wind-
driven 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.

Related Story: Weather Resistant Versus Water Resistant Barrier

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 as a complete system;
further, the system will be covered by the manufacturer’s warranty.

For more information, download the ebook “Innovation Leads to High-Performance Building Solutions” here.