New Walmart Store Brings Big Green Roof To Portland

The city of Portland, Oregon, is no stranger to green roofs. Since the 2008 launch of its Ecoroof Incentive program — which offers  up to $5 per square foot of a green roof project — the city has seen the installation of 330 vegetated roofs, with 100,000 square feet of that in 2011 alone. But in 2012, the city is set to gain a whole lot more green roof footage in a single project alone: the new Hayden Meadows Walmart store in North Portland.

This new, 90,000-square-foot Walmart location (which recently broke ground) will include a 40,600-square-foot Ecoroof, the largest private green roof in Portland and Walmart’s second such roof in the country. The plan calls for a roof that meets the City of Portland’s Ecoroof requirements with a layer of waterproof synthetic membrane root barrier topped with a growing medium, followed by a layer of vegetation. In that friendly manner of green roofs everywhere, the Hayden Meadows’ Walmart’s Ecoroof will extend the roof’s lifetime by two or three times, create habitat for birds and insects, decrease storm water runoff, absorb carbon dioxide, and help to save the building cash and carbon in the form of heating and cooling costs.

green roof portland

image via City of Portland

Other green features planned for this new store include lighting systems with daylight monitoring and skylights; eco-friendly flooring made with recycled fly ash; an HVAC system that recycles heat produced by the building’s freezer units; LED lighting in parking areas; recycled construction materials (such as steel and plastics); and a white membrane covering the remaining, un-vegetated portion of its roof. The store has retained space for a future Tri-Met bus stop, and will include bicycle racks.

The Ecoroof at the new Portland store is slated for both the main portion of the roof as well as the lower roof, which will be visible from Hayden Meadows Drive and the I-5 Freeway. Walmart plans to use perennial sedums along with a cascading groundcover and taller native plants on the building’s parapet.

Walmart’s first Ecoroof was installed on a store in Chicago in 2008. “The Hayden Meadows Ecoroof gives us an opportunity to test Ecoroof performance in a more moderate climate,” said Kimberly Sentovich, Senior Vice President, Pacific Division, Walmart, in a statement.

Susan DeFreitas has covered all manner of green technology for EarthTechling since 2009. She is a graduate of Prescott College for the Liberal Arts and the Environment, and has a background in marketing green businesses. Her work on green living has been featured in Yes! Magazine, the Utne Reader and Natural Home.

    • phor11

      I’d be interested in finding out how much weight the growing medium and plants add to the roof. Did they have to significantly change the support structures in order to pull this off?

      • http://twitter.com/manzanitafire Susan DeFreitas

        Here’s a guide for developers and DIYers from the City of Portland, which I imagine contains the info you’re looking for: http://www.portlandonline.com/bes/index.cfm?c=50818&a=331490

        • phor11

          Nice!
          So the building code requires a roof to withstand 25 pounds per square foot due to the possible snow load, and then the growing medium and plants only add another 20-22 pounds per square foot to that.
          Not bad!

    • zoya

      Wow! Its just imaginable to have such beautiful green roof, that looks totally amazing.Wonderful idea, thanks for sharing it.

      http://www.greenproindia.com/greenfloor.php