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 | Dec 9, 2016
California city’s plan for net zero building includes net zero water usage
Santa Monica city services building aims for highest level of sustainability.
Codes and Standards | Dec 8, 2016
WELL and BREEAM to align standards
The goal is to make it easier for projects pursuing both standards.
Codes and Standards | Dec 7, 2016
U.S. lumber industry pushes for import duties on Canadian softwood
The industry claims the product is being sold below fair market value.
Codes and Standards | Dec 5, 2016
International Construction Measurement Standards draft released
The goal is to improve consistency for calculating costs and reducing risk.
Codes and Standards | Dec 2, 2016
D.C. Council passes bill to reduce number of blighted properties
The new legislation reduces the amount of time a vacant property can qualify for a lower tax rate.
Codes and Standards | Dec 1, 2016
Passive House standard gaining influence in commercial sector
Some industry watchers predict it will become the base building code.
Codes and Standards | Nov 30, 2016
Researchers finding solutions to bird/building collisions
Glass facades pose a serious risk to birds and cause millions of avian deaths each year.
Codes and Standards | Nov 29, 2016
New OSHA rules to reduce fall and trip hazards
Employers can choose from a variety of fall protection systems.
Codes and Standards | Nov 29, 2016
Seattle imposes new construction regulation to address rat problem
The city ranks first in U.S. in rat population.
Codes and Standards | Nov 28, 2016
Construction groups sue New York City over crane safety regulation
The rule bans cranes from operating when wind exceeds 30 mph.