flexiblefullpage
billboard
interstitial1
catfish1
Currently Reading

White roofing isn’t always the best choice

Codes and Standards

White roofing isn’t always the best choice

Adverse effects include heat reflection onto nearby walls.


By Peter Fabris, Contributing Editor | November 16, 2017

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.

boombox1
boombox2
native1

More In Category


Standards

Design guide offers details on rain loads and ponding on roofs

The American Institute of Steel Construction and the Steel Joist Institute recently released a comprehensive roof design guide addressing rain loads and ponding. Design Guide 40, Rain Loads and Ponding provides guidance for designing roof systems to avoid or resist water accumulation and any resulting instability.



halfpage1

Most Popular Content

  1. 2021 Giants 400 Report
  2. Top 150 Architecture Firms for 2019
  3. 13 projects that represent the future of affordable housing
  4. Sagrada Familia completion date pushed back due to coronavirus
  5. Top 160 Architecture Firms 2021