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
| Dec 15, 2011
NRDC charges Maine governor with weakening green wood requirement
The FSC program is administered through the Leadership in Energy and Environmental Design (LEED) and requires wood to be harvested in a sustainable way.
| Dec 15, 2011
Post-tornado, Tuscaloosa seeks to create walkable urban, retail areas
Block sizes initially were limited to a maximum perimeter of 1,750 feet, with no side of the block being longer than 500 feet.
| Dec 15, 2011
Allentown, Pa. city council asked to repeal union-friendly law
The mayor of Allentown, Pa. asked the City Council to repeal a year-old ordinance that forces contractors to hire union workers for large city projects funded with state and federal dollars.
| Dec 13, 2011
LEED-EB outpaces LEED for new construction
The U.S. Green Building Council's (USGBC's) LEED certifications for existing buildings standard is outpacing LEED for new buildings for the first time.
| Dec 13, 2011
Regulators charge pervasive abuse of construction workers in Connecticut
Federal and state regulators say they have uncovered what they call "widespread noncompliance" with minimum wage and overtime laws in Connecticut's construction industry.
| Dec 13, 2011
Philadelphia mayor signs order for project labor agreements
Philadelphia Mayor Michael Nutter signed an executive order establishing project labor agreements for major public works projects in Philadelphia.
| Dec 13, 2011
Improved code requirements for attic ventilation
The Roof Assembly Ventilation Coalition (RAVC) participated in the development of the code.
| Dec 12, 2011
LEED-EB Outpaces LEED for New Construction
The U.S. Green Building Council’s (USGBC’s) LEED certifications for existing buildings standard is outpacing LEED for new buildings for the first time.
| Dec 12, 2011
Philadelphia Mayor Signs Order for Project Labor Agreements
Philadelphia Mayor Michael Nutter signed an executive order establishing project labor agreements for major public works projects in Philadelphia.
| Dec 12, 2011
Improved Code Requirements for Attic Ventilation
The International Code Council (ICC) recently published the 2012 International Residential Code (IRC) that includes improved code requirements for balanced intake and exhaust for ventilated attics.
