One of the signature public ecoroof projects in Portland sits atop the Portland Building in downtown – home to many of the City of Portland offices include the local drivers of ecoroof implementation, the Bureau of Environmental Services. Completed in 2006, this 18,000 square foot extensive roof melds seamlessly into the iconic architecture of this building. The design team was led by Macdonald Environmental Planning (Jason King as lead designer & project manager while at MEPpc) along with Carleton-Hart Architecture, KPFF Structural, and Athay & Associates for electrical engineering. As a retrofit, there were significant structural limitations to roof loading, making it necessary to fine-tune the depth and soil configuration to fall within project parameters. Using a specially blended soil mix, the project maximizes stormwater management (read a BES report of performance here) and minimizes irrigation and maintenance needs.
After a competitive bidding process, Snyder Roofing was selected to lead the construction, bringing in Teufel Landscape to provide installation for ecoroof system components. Using an array of adapted succulent species and hardy ornamental grasses, the team installed thousands of plants to achieve the desired planting effect. Irrigation was provided by efficient spray heads along with supplemental drip – with a goal of elimination of harmful PVC.
The finished roof shortly after construction shows a mosaic of colors and textures of the various species – and showing how this has evolved over time (this is also one of the images from our website header)
The project has had a few years to evolve and has been invaluable to The Bureau of Environmental Services, headquartered within the building, for research and monitoring. As you see here, BES Landscape Architect and Sustainable Stormwater Specialist (and local Ecoroof guru) Tom Liptan on site looking a temperature differences from exposed soil and non-vegetated areas. The site is also being monitored from stormwater management, and is performing well, with an average 64% retention rate.
The roof also appears in a number of BES Publications, such as this Cost-Benefit Evaluation of Ecoroofs Report from 2008, showing off the growth and coverage of vegetation after a couple of years.
A recent photo via the BES website from an adjacent building shows the evolution of the vegetation over time. The planting design includes organic shapes and creates color bands using different plant species, truly a site from above.