Green infrastructure, such as green roofs, green walls, and rain gardens, are excellent strategies to increase habitat and biodiversity on and around buildings, manage stormwater flows on site, treat greywater, lower surface air temperatures, and provide public amenities like community open space or educational experiences.
GGLO has designed over 100,000 square feet of green roofs on a variety of building types that provide a myriad of social, environmental andfinancial benefits. They are an excellent design strategy for meeting the triple bottom line objectives of people-planet-profit based sustainable design.
Environmentally, green roofs can help urban projects move towards pre-settlement conditions by restoring habitat and biodiversity and increasing stormwater retention on site. They also contribute to lowering the surface temperature of roof surfaces, an outcome that is particularly useful for countering the urban heat island effect when green roofs are grouped together.
Socially, green roofs can foster community by providing outdoor amenity spaces for local urban farming and gathering. Further, building residents and neighbors benefit from improved views from above and reduced noise levels from traffic and airplanes. They can bring incredible educational value to a site or building, and quickly communicate goals and how they are reached to residents and users.
Financially, green roofs can help increase the real estate value of a property and the marketability of a building as a whole. They can increase the lifespan of the roof membrane while lowering maintenance and replacement costs. On a case by case basis and depending on the governing agency, green roofs can help meet green building codes, like Seattle’s Green Factor; ease zoning requirements; and provide Floor Area Ratio (FAR) bonuses.
GGLO’s expertise in green roofs covers both deep soil intensive roofs and shallow soil extensive roofs. See our Green Roof Case Study (PDF) to learn more about our projects, and click here to find a PDF map of GGLO’s Green Roofs in Seattle, to see what we’ve built and what’s ‘on the boards.’
Similar to horizontal green roofs, vegetation can be applied to vertical surfaces to form Green Walls in an interior or exterior setting. Green Walls are not only decorative features, but can filter greywater or stormwater by absorbing pollutants, mineralizing the dissolved nutrients and making them available to plants. Green walls are usually found in urban environments where they contribute to reducing the overall temperatures of a building due to due to heat build-up from the absorption of solar radiation. They decrease local carbon dioxide emissions and noise while increasing humidity levels, trapping dust and creating habitat. Interior green walls can boost morale and productivity, by bringing fresher air and keeping occupants alert and with a feeling of overall health. Exterior Green Walls reduce solar heat gain and, by extension, building energy costs. They also provide protection from the effects of UV radiation and acid rain.
In the case of the Bertschi School Science Wing, greywater is collected from the classroom sinks, cleaned and dispersed by a continuous loop of evapotranspiration within an interior green wall; no greywater is discharged outside of the building envelope. Click here for a sequential diagram of the building’s ecological water flow.
Rain Gardens are an example of Low Impact Development (LID), a broad set of strategies aimed at re-thinking the built environment to bring it into balance with the natural environment.
Prior to development, rain falling on a site was absorbed into the ground and slowly drained to water bodies or recharged groundwater. With development came roofs, roads, and other hard surfaces that block water movement into the ground. These surfaces generate runoff that washes motor oil, pesticides, pet waste, and other untreated pollutants quickly and directly into rivers and lakes.
Rain Gardens counteract this process by passing the stormwater through organically enriched soil that filters out pollutants and either slows the release of the water into the storm system or percolates it into the ground. Generally designed with adaptive, native plant material, rain gardens do not require fertilizers, are tolerant of local climatic conditions and attract native birds and pollinators. Soil composition is critical for the successful installation of a rain garden. Soils must be permeable or should allow for water to percolate, through drywell or underground dispersion.
By installing Rain Gardens, water flowing from a site to a body of water will be slowed and cleansed – helping to rebuild and preserve the health of water bodies for the enjoyment of future generations.
Mark Sindell Principal, ASLA, LEED AP BD+C, Living Future Accredited (LFA)
Marieke Lacasse Principal, ASLA, LEED AP BD+C
“Seattle Green Roof Evaluation Project: Final Report” (1.6MB PDF), March 2007, Magnusson Klemencic Associates (web summary available on ENR.com)
Green Roof Performance Studies, Green Futures Lab, University of Washington
Heat Island Effect, US EPA
“Working Map of Existing Green Roofs within the Seattle City Limits” (PDF), City of Seattle, August 2010
Related Presentations & Publications:
GGLO Green Roof Case Study (1MB PDF)
GGLO’s Green Roofs in Seattle Map (1MB PDF)
Asa Flats + Lofts, Awards of Excellence, Intensive Residential Category, 2010, Living Architecture Monitor (1MB PDF)
Bertschi School Living Building Science Wing, Ecological Water Flow Sequential Diagram (4MB PDF)
“Green Factor: Redux, Leveraging Seattle’s Green Code to Create Urbane Spaces” (5MB PDF), August 31, 2011, Mark Sindell ASLA, LEED-AP BD+C and Zack Thomas ASLA, LEED-AP ND