Largest Pacific NW Green Roof Demonstrates Opportunity for Commercial BuildersPosted by Samantha on August 8th, 2014
One year ago, SolTerra began work on the largest green roof in the Pacific Northwest. Located on the Hayden Meadows Walmart in North Portland, this 40,000 square foot installation is unique in many ways beyond its size. To start, the drainage layer consists of a granular media (also known as pumice) rather than a polyethylene drainage plate which is used on most systems. This drainage layer is preferred because it mimics nature more accurately and does a better job with water retention, which in turn helps with healthier plant growth and improved stormwater management.
This photo, taken recently at the Hayden Meadows WalMart, shows significant growth in the last 6 months.
Other unique elements of this roof include experimentation with mulches, using either a stone or lava rock layer, habitat elements that included branches, bird baths, and gabion cages, and use of three different substrate depths. These variations in the install were chosen in order to study how the depths may effect stormwater management, which is especially important for commercial green roof installations like WalMart- a properly installed green roof can significantly decrease stormwater runoff fees for large flat roof buildings that can cost businesses hundreds of thousands of dollars a year. Given all of these factors, SolTerra was still able to hit the project timeline thanks to our incredibly hardworking field crew.
Navigating around vents and mechanical systems is one of the common challenges of green roof retrofits on commercial roofs such as Hayden Meadows WalMart.
Due to these several noteworthy install techniques, many eyes are on this project. The City of Portland is conducting additional research and collecting data on storm water management, and Portland State University is studying the eco impact using remote sensoring. Additionally, Walmart is looking at they Hayden Meadows green roof as a possible building model for all future stores. If it proves successful, this could potential reshape large scale commercial building development with incredible positive environmental effects. This summer, the SolTerra field crew got to see all the benefits of their hard work: we have found birds, ladybugs, bees, mushrooms, various insects, and a massive array of blooming windflowers during recent roof visits. It was an absolute joy to see the immediate natural response of our work, and to witness the impact that this roof is having not only on the building it's on, but on the construction industry as a whole.
Pathways allow visitors to navigate the green roof without compromising plants.
The Hayden Meadows WalMart green roof was completed in late 2013. Check out some progress photos of this project, as well as our other completed green roofs, over in our gallery!