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
Resiliency | Sep 30, 2022
Designing buildings for wildfire defensibility
Wold Architects and Engineers' Senior Planner Ryan Downs, AIA, talks about how to make structures and communities more fire-resistant.
| Sep 30, 2022
Lab-grown bricks offer potential low-carbon building material
A team of students at the University of Waterloo in Canada have developed a process to grow bricks using bacteria.
| Sep 27, 2022
New Buildings Institute released the Existing Building Decarbonization Code
New Buildings Institute (NBI) has released the Existing Building Decarbonization Code.
| Sep 22, 2022
Gainesville, Fla., ordinance requires Home Energy Score during rental inspections
The city of Gainesville, Florida was recently recognized by the U.S. Dept. of Energy for an adopted ordinance that requires rental housing to receive a Home Energy Score during rental inspections.
| Sep 19, 2022
New York City construction site inspections, enforcement found ‘inadequate’
A new report by the New York State Comptroller found that New York City construction site inspections and regulation enforcement need improvement.
| Sep 16, 2022
Fairfax County, Va., considers impactful code change to reduce flood risk
Fairfax County, Va., in the Washington, D.C., metro region is considering a major code change to reduce the risk from floods.
| Sep 13, 2022
California building codes now allow high-rise mass-timber buildings
California recently enacted new building codes that allow for high-rise mass-timber buildings to be constructed in the state.
| Sep 8, 2022
U.S. construction costs expected to rise 14% year over year by close of 2022
Coldwell Banker Richard Ellis (CBRE) is forecasting a 14.1% year-on-year increase in U.S. construction costs by the close of 2022.
| Aug 29, 2022
Montana becomes first U.S. state to approve 3D printing in construction
Montana is the first U.S. state to give broad regulatory approval for 3D printing in building construction.
| Aug 25, 2022
New York City’s congestion pricing aims to reduce traffic, cut carbon
Officials recently released an environmental assessment that analyzes seven different possible pricing schemes for New York City’s congestion pricing program.