Effects of green, white roofs to be compared at Walmart in Oregon

Portland State University will construct a 40,000-sf green roof research site on the top of a new Walmart store in North Portland, Ore., and compare it to a 52,000 sf section of roof with a white membrane.

The study provides an opportunity to evaluate the effectiveness of green and white roofs on the same building. The Green Building Research Laboratory at Portland State will compare how well each roof type filters rainwater and whether energy use and heat-island issues can be reduced.

The green roof is being installed in three sections, each designed to test various kinds of green roof design, such as materials and soil depth.

(http://www.bizjournals.com/portland/blog/real-estate-daily/2013/10/psu-investigates-how-green-roofs-work.html)