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 | May 22, 2018
Registration open for 2018 National Energy Codes Conference
U.S. Department of Energy event to be held July 15th-17th in Austin.
Codes and Standards | May 21, 2018
New standard tests quietness of floors
ASTM International method will help manufacturers test their flooring materials.
Codes and Standards | May 17, 2018
California will require solar panels on most new homes
Projected to add $10,000 to cost of new homes.
Codes and Standards | May 16, 2018
New resources offer tips on off-site construction
NIBS documents address using pre-cast concrete, and commercial and legal considerations of modular construction.
Codes and Standards | May 15, 2018
Blast testing of loaded mass timber structures yields positive results
Four tests covered a spectrum of blast loads.
Codes and Standards | May 14, 2018
Maryland makes general contractors liable for failure of subs to pay employees
GCs could have to pay for up to three times the wages owed.
Codes and Standards | May 10, 2018
Data collection, machine learning boost building efficiency
Sensors, software algorithms squeeze out waste.
Codes and Standards | May 9, 2018
OSHA and state safety agencies write more than 100 silica citations in 6 months
Actions tending to come with investigation of other site conditions.
Codes and Standards | May 8, 2018
Powerhouse coalition builds energy positive buildings
The goal: build buildings that provide more power than they cost to build, run, and demolish.
Codes and Standards | May 7, 2018
Plan advances in Los Angeles for Climate Emergency Mobilization Department
Would oversee efforts to reduce greenhouse gas emissions across the city.
