High-performing Air Barriers: The Unsung Hero of Construction
Air barriers are no longer just a passing consideration. They are not only federally mandated, but also demanded by code-conscious and sustainability-oriented building owners and occupants who are in the know. For good reason, too.
A high-performing air barrier means greater comfort at a lesser cost.
Based on simulations, the National Institute of Standards and Technology (NIST) estimates a properly installed air-barrier system can reduce air leakage by up to 83%, cut gas bills by more than 40%, and save on electrical use by more than 25%. The Air Barrier Association of America (ABAA) provides a free energy savings calculator on their website for anyone to use, helping quantify energy savings based on the use of air barriers.
A good air barrier provides a separation between controlled indoor air and uncontrolled outdoor air. When used in combination with a good thermal barrier, a well-constructed air barrier will keep the occupants’ space at a more constant temperature without excessive air conditioning or heating. This reduces occupant and building utility costs as well as costs of maintaining heating and cooling equipment.
A high-performing air barrier extends a building’s lifecycle.
“Uncontrolled air flow is the greatest source of moisture and condensation damage in exterior walls, as compared to simple vapor transmission. And uncontrolled moisture is the greatest cause of deterioration of building materials.” – Judd Peterson, AIA, president of the Judd Allen Group, Edina, Minn.
The National Air Barrier Association (NABA) estimates 90% of damage is caused by moisture. It warns that moisture can wreak havoc in many ways, including rot, rust, and premature degradation of envelope and structural supports. The NABA also reports that the financial impact of reparation versus initial proper air barrier application is roughly 50% higher.
A properly installed air barrier controls moisture penetration between spaces, which limits mold growth while also providing a first layer of defense against fire and smoke from an adjoining space.
Anything worth doing is worth doing well.
Quality materials and correct installation make all the difference. A sponsored study out of Kansas State University underscores this thinking with results showing that “small voids in wall cavities or at the end of a batt of 1 to 2 percent of the insulation area can result in a 25 to 40 percent loss of R-value.”
When it comes down to it, your high-performance air barrier must have at least the following characteristics:
- It will be impervious to airflow.
- It will be continuous over an entire building or over the space that it is intended to contain. Partial air barriers have limited to no effectiveness.
- It will be able to withstand forces that are placed on the air barrier both during and after construction of the building. This includes deflection of building materials from increased loads as building construction continues and forces of weather and other environmental factors when the building is certified for occupancy.
- It will be durable over the expected life of the building. Durability and expected life are relative concepts, but with routine maintenance and care, air barriers should not need extensive repairs or replacements at any time while the building is used and occupied.
Manufacturers that take the guesswork out of air barrier selection and application set up installers, and the buildings they work on, for success. Energy-efficient products like DELTA®-VENT SA are tried and true “go-tos” because they’re not only effective, but also simple and straightforward to install. 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.
Put it to the test.
Although not compulsory by code, airtightness testing, as reported by the ABAA, is a performance-based option that many designers are requiring. The test measures air leakage rates through a building envelope under controlled pressurization and depressurization. The ABAA recently published a new standard for whole building airtightness testing called “Standard Method for Building Enclosure Airtightness Compliance Testing”. Results of the test can be used to assess whole building systems, including current products and installation, as well as improve energy efficiencies for a higher score on the “green” scale.
Behind the scenes but ahead of the curve.
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.