Although LEED and ASHRAE 90.1 (Energy Standard for Buildings Except Low-Rise Residential Buildings) standards require or reward use of white “cool” roofing to mitigate urban heat island effects, it is not always the best choice of material.
Cool roofs can cast heat where it is not wanted. “Architects and roof consultants need to be aware of potentially adverse thermal effects when choosing roof membranes, particularly where roof surfaces are adjacent to walls that can be affected by bounced sunlight,” says Elizabeth Grant, associate professor in the School of Architecture + Design at Virginia Tech.
Choosing the best material for a commercial roof is a nuanced decision requiring a careful examination of the application. “Roof selection is an architectural issue,” Grant said. “It’s not as simple as slapping a white roof on everything to gain a LEED point.”
The study compared the thermal impact of white and black roofs. The black roof heated the air within 5 ½ inches, but there was no difference in air temperature impact for black or white roofing above that zone. Researchers also found that electrical metallic tubing and glazed and precast concrete wall panels near white TPO roofing were 3 to 9 degrees Fahrenheit warmer than those near black EPDM roofing.
Related Stories
| Jul 12, 2012
Federal budget chief to explain impact of pending defense cuts before Congress
Office of Management and Budget Director Jeffrey Zients is scheduled to testify before the House Armed Services Committee Aug. 1 to explain the possible effects of $500 billion in defense cuts on U.S. companies, including those in the design and construction industry.
| Jul 12, 2012
Pennsylvania legislature moves to prevent undocumented workers on public construction projects
Legislation to prevent undocumented workers from being hired by construction companies working on state-funded projects passed the Pennsylvania Legislature.
| Jul 12, 2012
New York’s One Bryant Park Bank of America tower is first new high-rise to achieve LEED Platinum
The new One Bryant Park Bank of America tower in midtown Manhattan is the first new commercial high-rise to achieve LEED Platinum certification.
| Jul 12, 2012
OSHA launches campaign to prevent heat illness
The Occupational Safety and Health Administration has launched its 2012 Heat Illness Prevention Campaign to educate employees and their employers about the hazards of working outdoors in heat, and how to prevent heat-related illnesses.
| Jul 12, 2012
Contractors have increasing concerns over new federal hiring quotas
A proposed rule by the U.S. Department of Labor's Office of Federal Contract Compliance Programs to increase disabled- and veteran-worker hiring quotas for federal contractors continues to raise deep concerns among contractors.
| Jul 5, 2012
Veterans Administration threatens to pull contract on new Orlando medical center
The Veterans Administration asked contractor Brasfield & Gorrie to get more workers on the job and figure out a way to get the job done faster, or the VA would pull the contract on the much-delayed Orlando VA Medical Center.
| Jul 5, 2012
Cost to contractors for new federal hiring quotas much higher than estimated, AGC says
Administration officials significantly underestimated the cost to construction employers of proposed new hiring quotas for federal contractors, according to analysis by the Associated General Contractors of America.
| Jul 5, 2012
Roof membrane could have prevented roof parking deck collapse, specialist says
The collapse of a section of a roof parking deck at the Algo Centre Mall in Elliot Lake in Ontario, Canada could have been prevented if the structure had a membrane, according to a concrete expert and specialist in structure analysis at McMaster University.
| Jul 5, 2012
New Joplin, Mo. hospital being built to withstand tornado that destroyed predecessor
After the May 22, 2011, EF-5 tornado destroyed St. John’s Regional Medical Center in Joplin, Mo., architects and engineers analyzed how the nine-story structure reacted to the storm.