Portland Walmart to Feature Green Roof

PORTLAND, Ore. — Portland State University’s (PSU) Green Building Research Laboratory is partnering with Walmart to build a green roof on top of a local North Portland store. The university and Walmart will participate in a two-year research partnership to construct a 40,000-square-foot green roof and collect in-depth data to benefit future projects. The green roof project will be the largest in the city of Portland when Walmart’s new Hayden Island Meadows store opens Nov. 13.

“The data we collect will help the green building industry improve upon the many benefits provided by green roofs — from reducing heat island effects to improving overall building performance,” said David Sailor, director of the PSU Green Building Research Laboratory and professor of mechanical engineering, in a statement. “This research project will lead to better green roof design for buildings around the world.”

The research partnership will study how green roofs filter rainwater, enhance energy efficiency, mitigate heat island effects and improve wildlife habitats. Embedded sensors on the roof will measure surface temperature, water flow and other building operations data. Impacts both inside and outside the building will be measured.

The roof will serve as both a green roof for building occupants and as a research classroom for PSU students.

“It’s a huge opportunity for us to engage students in research that’s connected both to the environment and the community,” Sailor said.

The remaining 52,000 square feet of the white membrane rooftop, which will also feature sensors, will offer a side-by-side comparison to further study the effects of green roofs. The findings of the Portland green roof project will also be measured with the findings of a green roof installation on a Chicago Walmart, providing additional comparison data of the two climates. The Portland green roof will be Walmart’s first on the West Coast.

The vegetative roof is being installed in three sections. Each of those three sections concentrates on specific elements of green roof design such as materials and soil depths.

Several Portland organizations will also have a hand in the green roof research project. Portland’s Bureau of Environmental Services will measure stormwater runoff, environmental consulting firm Cadmus Group will monitor rooftop air conditioning units and the Audubon Society of Portland will conduct surveys in order to contribute to habitat monitoring.