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The award for intensive, new construction, went to Number Ten Architectural Group for the Ducks Unlimited National Headquarters in Winnipeg, Manitoba. The nonprofit organization is dedicated to the conservation of waterfowl, and the building, adjacent to a wetland, was designed to blend with the prairie surroundings from the "duck's eye view."

Two green roofs totaling 28,000 square feet (2600 square meters) provide places for habitat observation. Their construction includes 16 inches (400-millimeters) of growing medium, wire mesh for rodent control, a 2-ply SBS Soprema membrane system, high- and low-level drains, filter cloth on a granular drainage layer, and rigid insulation. The soil depth of the green roof and berming on the sides of the building eliminate the need for a chiller. Every three years, the prairie grasses are repropogated through a controlled burn on the upper roof.

Combining intensive and extensive systems is the award-winning Peggy Notebaert Nature Museum Green Roof Demonstration Garden at the Chicago Academy of Sciences. The landscape architecture firm, Conservation Design Forum retrofitted the roof as a museum exhibit directly visible from several vantage points. It has four progressively thicker systems along its 200-foot (60-meter) length and features a drip irrigation system, a solar-driven water recirculating pump, a retaining wall, and over 80 species of native and hardy ornamental plants.

The museum's green roof systems include a Sarnafil 60 ML waterproofing membrane and gravel drainage layer. Reflecting different loading capacities of the building, there is a 2.5-inch (65-millimeter) deep wetland section, a 4-inch (100-millimeter) deep transitioning extensive section, and 8- to 10-inch (200 to 255-millimeter) sections. The project supports the museum's plant survivability research.

New Green Construction

The Gap Inc. offices in San Bruno, California, designed by William McDonough + Partners received the award in the extensive, new construction category. The building was designed to blend into a steep savannah site. The 69,000-square-foot (6400-square-meter) undulating green roof is covered in native grasses and wildflowers. Its design shapes both the building's profile and its relationship to the physical environment. It also improves mechanical performance, thermal comfort, and stormwater management.

The system uses an American Hydrotech waterproofing membrane, and 6 inches (150 millimeters) of growing medium. Annual energy cost projections predict a simple payback of 11 years. Using native grasslands, the roof is a self-sustaining ecosystem requiring minimal maintenance.

The landscape architecture firm Olin Partnership won an award for its combination intensive/ extensive roof on the Church of Jesus Christ of Latter-Day Saints Conference Center, in Salt Lake City, Utah. The eight-acre (3.2-hectare) multilevel roof was designed to integrate with the nearby mountain landscape and not overwhelm the adjacent Mormon Temple. The green roof design incorporates the elements of water, stone, trees, and meadows. The system includes a Hydrotech membrane and drainage mat, 140N Mirafi geotextile filter fabric and a growing medium of expanded aggregate and organic matter, with a depth ranging from 2 inches to 4 feet (50 to 1200 millimeters).

Coniferous trees are placed along free standing walls anchored to the roof structure to accommodate the soil depths. The roof vastly reduces runoff for the site and lowers the cooling load for the 20,000-person assembly hall.

Katrin Scholz-Barth Consulting was awarded in the retrofit extensive category for the Montgomery Park Business Center.

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The jury for the awards program included William Thompson, FASLA, editor of Landscape Architecture Magazine; Monica E. Kuhn, BES, B.Arch, founder of the Rooftop Garden Resource Group; N. Marcia Jiménez, commissioner of the City of Chicago's Department of the Environment; Michael Gibbons, FCSI, CCPR, head of the Green Roof Task Group of the ASTM and president of Architectural Designs; Robert Herman, horticultural consultant, Uncommon Plants; and Steven W. Peck, founder and executive director of Green Roofs for Healthy Cities.

For the Peggy Notebaert Nature Museum Green Roof Demonstration Garden at the Chicago Academy of Sciences, the lack of loading capacity prevents the roof from being directly accessible to the public, but it displays many green-roof principles. Photo: Courtesy Green Roofs for Healthy Cities The Gap Inc. offices in San Bruno, California, designed by William McDonough + Partners, blends into its site near the San Francisco International Airport. The mass of the roof attenuates sound transmission by up to 50 decibels, providing an acoustic barrier to air traffic. Photo: Mark Luthringer The Church of Jesus Christ of Latter-Day Saints Conference Center in Salt Lake City, Utah provides an expanse of meadow and trees as an oasis for meditation and contemplation in an urban context. Photo: Courtesy Green Roofs for Healthy Cities   Click on thumbnail images to view full-size pictures.