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 | Oct 4, 2017
Ambitious but realistic increase in clean energy would cut GHG emissions by 80% in the U.S.
NRDC report says goal can be achieved with existing tools.
Codes and Standards | Oct 3, 2017
Reducing duct leakage is focus on latest green building standards updates
ASHRAE 189.1 broadens testing requirements to include more types of ducts.
Codes and Standards | Oct 2, 2017
Nationwide retrofit strategy in Canada could cut 51% of emissions from large buildings
The roadmap provides government and industry with a targeted plan.
Codes and Standards | Sep 28, 2017
Resources available for new OSHA respirable crystalline silica regulation
NRCA offers compliance tools for contractors.
Codes and Standards | Sep 28, 2017
New tool compares HVAC system efficiency
IAPMO and Hydronics Industry Alliance unveil BEST to evaluate systems in early design phase.
Codes and Standards | Sep 26, 2017
Anti-drone technology can ward off unauthorized drone flights
The technology can be used to prevent terrorist attacks and spying.
Codes and Standards | Sep 25, 2017
How-to guide to renovating shopping centers available
E.U. research project focuses on energy efficiency and occupant comfort.
Codes and Standards | Sep 21, 2017
After construction crane collapses during Irma, regulations questioned
Cranes rated for 140 mph winds didn’t hold up to 100 mph gusts.
Codes and Standards | Sep 20, 2017
Energy efficiency measures pay off in some not-so-obvious ways
Access to better financing, tax incentives, rent premiums, among the benefits to greener buildings.
Codes and Standards | Sep 19, 2017
Benchmarking regulations prompt jump in green certified properties
2016 saw a slight rise in total certified U.S. green office space.