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
Codes and Standards | Jan 17, 2022
AISC seeks comments on draft earthquake standard for steel buildings
Includes new limits for cross-sectional slenderness of steel columns based on latest research.
Codes and Standards | Jan 12, 2022
California’s wildfire building code significantly reduces structural loss
As other states consider upgrading their codes, Golden State provides useful model.
Codes and Standards | Jan 12, 2022
Regulator holding back climate-friendly, energy-saving equipment deployment, critics say
Heat pumps, solar power could be made more accessible for low-income communities in Massachusetts.
Codes and Standards | Jan 11, 2022
Cost hikes drive nearly one million renters out of homeownership qualification in 2021
Household income needed to pay a mortgage rose to $62,872 from $55,186.
Codes and Standards | Jan 10, 2022
New ratings services focus on climate risk for homeowners
Efficacy of models used in risk assessment varies.
Codes and Standards | Jan 6, 2022
Virginia contractors having a tough time finding diverse subs to meet state goals
Survey of primes may indicate similar issues at federal level.
Codes and Standards | Jan 5, 2022
Boston drops parking requirements for affordable housing
Measure expected to spur new projects.
Codes and Standards | Jan 4, 2022
Dept. of Energy Better Climate Challenge aims for 50% GHG emission reduction by 2030
Program offers technical assistance and peer-to-peer knowledge sharing.
Codes and Standards | Jan 4, 2022
Architects at New York firm take steps to unionize
Support for unionization reported at two other New York firms.
Codes and Standards | Jan 3, 2022
Biden’s executive order for a carbon-neutral government includes green materials mandate
As a driver of demand, federal procurement impact could ripple through the economy.