EcoCenter, San Francisco
Green roof size: 1,100 square feet
Award recipient: Habitat Gardens (project manager, horticulturalist, designer) Project Team
Architect: Toby Long
Client: Literacy for Environmental Justice
Green roof system: Opti-Green
Waterproofing: HB Urethane Foam
Parapet design: Evo Design; Casey Lyon, Founder, Habitat Gardens
Literacy for Environmental Justice (LEJ) is an organization whose mission is to foster an understanding of the principles of environmental justice and urban sustainability in young people in order to promote the long-term health of communities. It was the recipient of a grant under the American Recovery and Investment Act of 2009 (ARRA) and selected Habitat Gardens, a landscape and living architecture firm, as the primary contractor to complete a major project at The EcoCenter at Heron’s Head Park in San Francisco, a 23-acre wetland park in Bayview Hunters Point. The work for the project consisted of installing two extensive living roofs (1,100 square feet in total). The project also integrated green infrastructure around the building in the form of permeable pathways, constructed wetlands as part of the building’s waste treatment system, and a rainwater catchment system.
The conditions on the EcoCenter roof are fairly harsh with high winds and sun exposure that dries out the growing media quickly. The vegetation consists of 39 plant species that are endemic to the Bay Area region with the goal to attract birds, bees, and butterflies. The majority of the plants were sourced from LEJ’s own nursery. Since this is also San Francisco's first 100-percent off-grid building, emphasis was given to creating a low maintenance roof. Integrated water management principles were also implemented. Plants are all drought tolerant and the irrigation system (which is aided by two 5,000-gallon galvanized tanks) was designed as a closed loop system in order to save water due to waste and runoff.
Recycled materials were used wherever possible. A capillary mat was installed on top of the foam roof to increase water storage and retention. Triangular drainage channels were placed on top of the capillary mat to carry excess water to roof drains or scuppers. The drainage channels would eventually be embedded in granular drainage media. The capillary mat was made from recycled polypropylene while the drainage channels were made from 100-percent post-consumer recycled content. The filter fabric and parapet filler were also created from recycled materials. Gravel was purchased from a local quarry just off the property, and rocks and driftwood were collected from Heron’s Head Park.
The roof is used as an education tool for the youth showcasing that plants the grow on the property can also grow on the roof. It has also served as a useful source of employment in the area. The installation created 31 new jobs, and many of the youths who helped to grow plants in the nursery now work as facility tour guides.
Steven W. Peck is the founder and president of Green Roofs for Healthy Cities, the non-profit industry association with a mission to develop the green roof and wall industry across North America. For more information visit greenroofs.org. Readers are invited to join GRFHC at CitiesAlive to meet the award winners and learn more about these outstanding green roof and wall projects: citiesalive.org.