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
| Jan 18, 2012
Report analyzes residential hurricane codes in 18 states
The Insurance Institute for Business & Home Safety (IBHS) released a new report analyzing residential building codes in 18 hurricane-prone coastal states along the Gulf of Mexico and the Atlantic Coast.
| Jan 18, 2012
Death in Chicago high-rise apartment fire blamed on fire code
The death of a Chicago woman who stepped off her elevator into a blazing inferno last week has underscored the need for fire sensors in elevators.
| Jan 18, 2012
California approves open cell spray foam for energy efficiency standards
The California Energy Commission (CEC) now recognizes open-cell spray foam as an accepted insulation in its 2008 Building Energy Efficiency Standards.
| Jan 5, 2012
Building to LEED standards now an 'easy call' from cost standpoint
Once seen as a cost burden, building to LEED standards is now an "easy call," according to Dan Probst, chairman of energy and sustainability for real estate management and development firm Jones Lang LaSalle.
| Jan 5, 2012
Minnesota's GreenStep Cities program aids communities in winning grants
GreenStep Cities, a Minnesota initiative, was designed to provide greater recognition to the state's communities for achievements in meeting sustainability standards and goals.
| Jan 5, 2012
Some ADA accessibility rules change in 2012
Some changes to the Americans with Disabilities Act go into effect beginning March 15, 2012.
| Jan 5, 2012
Ontario's stringent energy code has builders concerned over indoor air quality
Some Ontario builders are worried that new building code requirements with stricter energy efficiency measures could lead to poor indoor air quality.
| Jan 5, 2012
New law bars Defense Department from new LEED certifications
The Defense Department will not be allowed to use any money to certify its buildings LEED Gold or Platinum, under a law President Obama signed Dec. 31.
| Jan 5, 2012
Some ADA accessibility rules change in 2012
Some changes to the Americans with Disabilities Act go into effect beginning March 15, 2012.
| Jan 3, 2012
New SJI Rule on Steel Joists
A new rule from the Steel Joist Institute clarifies when local reinforcement of joists is required for chord loads away from panel points. SJI members offer guidance about how and when to specify loads.
