The City of Portland, Oregon and the Portland Housing Authority have added a 5,40 square foot greenroof, or ecoroof as they are referred to here, atop a 8,500 square foot 10-story apartment building. The ecoroof covers 60% of the roof. The building was designed by OTAK Architects, the greenroof system used is the Garland Company’s GreenShield program and the waterproofing is Garland’s StressPly Plus polymer modified membrane. Many low growing sedums, such as Sedum oreganum, and other succulents provide groundcover with some native wildflowers and grasses for accents. The roof was irrigated the first year for proper plant and root establishment and is flourishing nicely.

The site has been instrumented and monitored for stormwater retention and flow capabilities and tests are being performed on two soil depths, with plot areas of 2″ and 4″. The program is funded by the City of Portland, Bureau of Environmental Services and preliminary results are very encouraging. For complete stormwater data, details and charts please check the Autumn 2001 Green Roof Infrastructure Monitor or contact Ryan Retzlaff, Environmental Technician, City of Portland, OR at 503.823.7875 or at ryanr@bes.ci.portland.or.us.