A One-time Capital Investment to Improve Your Building’s Thermal Performance Is Environmentally and Fiscally Responsible

CI provides a number of advantages. It not only reduces thermal bridging at wall studs, but also reduces thermal bridging through all exterior framing members with the exception of the fasteners. Another CI advantage is it creates a uniform surface for more effective air-barrier application and water-management interfaces. CI also increases wall-cavity temperatures, which helps mitigate in-wall condensation when moisture-laden air comes in contact with colder building components.

CI materials commonly used are:

  • Extruded polystyrene
  • Closed-cell spray foam
  • Expanded polystyrene
  • Polyisocyanurate

Rigid Fibrous Insulation

This is a typical wall-roof assembly. There is air leakage into and out of everything and everywhere. There is no membrane under the parapet flashing, no air control in the roof or wall assembly and no vapor-control layer.

This is a typical wall-roof assembly. There is air leakage into and out of everything and everywhere.
There is no membrane under the parapet flashing, no air control in the roof or wall assembly and no vapor-control layer. Image: Building Science Corp.


A continuous air barrier is more than just a building wrap. It employs multiple strategies and products to control airflow throughout the entire enclosure, which is key to the performance of insulation. According to a 2005 Gaithersburg, Md.-based National Institute of Science and Technology study, energy savings can be realized by undertaking specific airtightness measures. The study, “NIST report 7238”, concluded that air infiltration in commercial buildings could be reduced by 80 percent by employing air barriers, resulting in 25 to 40 percent energy savings.

ASHRAE 90.1 2010 requires commercial buildings have continuous air barriers and the materials that make up the air barrier system be tested to ASTM standards.

The Walpole, Mass.-based Air Barrier Association of America sets strict requirements and functions for air barriers. Common air barriers are:

  • Sheet goods or wraps
  • Fluid-applied products
  • Board stock taped and sealed
  • Spray foam

Our Responsibility

The amount of energy buildings use accounts for probably 36 percent of all our nation’s energy use and 25 to 30 percent of all our greenhouse gases; a big component of that is heating and cooling. For example, U.S. K-12 schools spend more on energy than they do on textbooks and computers—$7.5 billion annually. Seventy percent of school energy costs are space conditioning and lighting.

Energy-efficient building is more than just specifying energy-efficient products. Delivered efficiency starts with an integrated design process that considers all building-science principles to ensure real-world performance. Not only is improving your building’s energy performance the environmentally responsible thing to do, but as energy costs continuing increasing it’s the fiscally responsible thing to do.

Roofing Insulation Advances

In commercial buildings, one of the major sources of envelope energy loss is through the roof, especially in large warehouse-type buildings, like big-box retail stores. Advancements in roofing have led to many new retrofit applications that will increase roof performance and energy efficiency. For example, a spray foam roofing system has been selected to reroof more than 500,000 square feet of terminal and maintenance buildings at Cleveland-Hopkins International and Burke Lakefront airports in Cleveland. The roof system also recently received a severe hail rating from FM Approvals, the testing and certification arm of Park Ridge, Ill.-based FM Global, which is one of the world’s largest property insurers.

“The new spray foam roof was more cost-effective because we could apply it directly over our old roof, and it has helped us minimize disruption to passengers,” says Rob Henderson, building maintenance manager, Cleveland Airport System. “As a bonus, our insurance premiums are now lower because our insurer, FM Global, approved the roof components.”Solstice LBA from Honeywell International

In addition, the closed-cell spray foam insulation features a next-generation blowing agent with a global warming potential of 1, significantly lower than previous-generation hydrofluorocarbon blowing agents. The blowing agent is nonflammable, has received Washington, D.C.-based U.S. Environmental Protection Agency approval under the Significant New Alternatives Policy Program and is not a volatile organic compound.

“From a contractor’s standpoint, there is little to no difference from the blowing agent we have used for years,” says Jack Moore, project engineer, West Roofing Systems, La Grange, Ohio. “This was virtually a drop-in; it didn’t require any special equipment or additional education for its application.”

Moore also notes the product is developing higher compressive strength for a more durable roof surface. He adds: “We are also seeing a slightly greater yield out of the product—somewhere in the neighborhood of 8 to 10 percent, which isn’t a lot but when you’re spraying a lot of the product, 8 to 10 percent does add up. We’re getting an environmental benefit, a performance benefit and we’re also getting more material out of the same volume as we were before the switchover to the new blowing agent.”

Retrofit Materials

Spray polyurethane foam roof system: West Development Group LLC
Blowing agent: Solstice LBA from Honeywell International Inc.

About the Author

Steve Easley
Steve Easley is principal of Steve Easley & Associates, Danville, Calif. He is an internationally recognized construction consultant, specializing in solving building-science related problems and educating building industry professionals and their trade partners. His mission is to create structures that are durable, energy efficient, healthy, and comfortable to live and work in.

Be the first to comment on "A One-time Capital Investment to Improve Your Building’s Thermal Performance Is Environmentally and Fiscally Responsible"

Leave a comment

Your email address will not be published.


*


%d bloggers like this: