Vegetated roofing is experiencing a growth spurt across the U.S. Projects have been appearing on federal buildings in the nation’s capitol; on commercial projects as far west as California; and on various buildings in our nation’s heartland, where Chicago boasts the largest area of vegetated roofing in North America with about 4 million square feet (371600 m2). With President Barack Obama’s focus on the environment, green roofs likely will continue their upward climb. The benefits of vegetated roofs, such as sound insulation, possible reduced heating and cooling costs, the potential to reduce or eliminate roof drains, aesthetics, habitat for birds and insects, and food production make them a sustainable choice for urban environments. The Fairmont Waterfront Hotel in Van- couver, British Columbia, Canada, grew herbs, flowers and vegetables on its 2,100-square-foot (195-m2) acces- sible roof and saved $30,000 per year in food costs, according to Toronto-based Green Roofs for Healthy Cities. The GRHC “Third Annual Green Roof Market Industry Survey” revealed the green-roof market grew by 30 percent in 2007, a 5 percent increase compared to the 2006 market growth rate of 25 percent. Total square footage in 2007 was 2.4 million square feet (223666 m2). The survey, which GRHC estimates encompasses about 60 percent of total market activity, was based on square footage of green-roof projects installed by GRHC’s corpo- rate members in 2007. After Chicago, the North American cities with the most vegetated-roof square footage are Baltimore; Brooklyn, N.Y.; Burnaby, British Columbia, Canada; Calgary, Alberta, Canada; Royersford, Pa.; Toronto; Virginia Beach, Va.; Washington, D.C.; and Wilmington, Del.
CENTER FOR URBAN ECOLOGY/ WASHINGTON, D.C. /
About 52 percent of Washington is covered with impervious surfaces, such as streets, buildings and parking lots, which helped to inspire the Center for Urban Ecology to install a 7,000-square-foot (650-m2) extensive vegetated roof atop its headquarters. A modular green-roof system was chosen as the solution because of its design simplicity. The soil and plant media are pre-installed in 100 percent recycled plastic modules that then are placed on the roof. The roof will retain storm water; potentially improve insulation properties; prolong roof life; reduce ambient-air temperatures to mitigate the urban heat-island effect; minimize dust and particulate matter; and provide a habitat for birds, bees and butterflies.
PROJECT SUBMITTED BY WESTON BUILDING SOLUTIONS INC., WEST CHESTER, PA., WWW.GREENGRIDROOFS.COM
THE EVELYN PEASE TYNER INTERPRETIVE CENTER / GLENVIEW, ILL. /
Set amidst Air Station Prairie, a 32 1/2-acre (13-hectare) remnant of tall-grass prairie north of Chicago, the 3,000-square-foot (279-m2) center educates visitors about the history and ecology of the Illinois prairie ecosystem while serving as a showcase for cutting-edge technology and techniques in green-building development. In 2007, the project received LEED for New Construction Platinum certification from the U.S. Green Building Council, Washington, D.C. One of the contributing factors to certification was the center’s 4,000-square-foot (372-m2) vegetated roof, which was planted with native and ornamental species to replace lost land area from the building footprint. The vegetated area covers three-fourths of the building’s roof. Any runoff from the roof slides down rain chains into a re-established prairie where it migrates through the soil before entering wetland systems adjacent to the building. The building is placed on a pin foundation to create minimal site disturbance and allow the building to rest between two existing wetlands without compromising either one or harming the building. Photovoltaic panels and a geothermal loop create on-site renewable energy.
PROJECT SUBMITTED BY WIGHT & CO., CHICAGO, WWW.WIGHTCO.COM
CHRISTIE PLACE / SCARSDALE, N.Y. /
Christie Place is a luxury townhome community located north of New York. Developed by Ginsburg Development Cos., Scarsdale, and built by FM Home Improvement, East Orange, N.J., the buildings match the existing Tudor-style architecture of the Scarsdale village center. The vegetated roof includes a terrace area and plaza area. The terrace area is home to trees and shrubbery, and the plaza features grass, pavers and bluestone. Both areas include EPDM adhered to the deck, pressure-sensitive flashing to strip in the field seams, protection fabric and a geomembrane root barrier. The terrace area also uses drainboard, biobarrier root-protection fabric, intensive growth media, and specifically chosen plants and landscaping to achieve its functional and aesthetic goals. The plaza area features drainboard and pavers set into a shallow, coarse sand bed.
PROJECT SUBMITTED BY CARLISLE SYNTEC, CARLISLE, PA., WWW.CARLISLE-SYNTEC.COM
MULTNOMAH COUNTY CENTRAL LIBRARY / PORTLAND, ORE. /
A new vegetated roof atop this library replaced the former leaking roof. The vegetated roof, which cost $180,000 and covers 7,188 square feet (668 m2), contains more than 17,000 sedums and grasses. An interlocking tray system met the county’s need for sustainability and cost effectiveness. The roof is one of the county’s more than 25 adopted sustainability initiatives. Benefits will include minimized rainwater runoff and pollution of nearby rivers, decreased energy costs, extended roof lifespan and mitigated urban-heat-island effect. The general contractor was Snyder Roofing of Oregon LLC, Tigard, Ore.
PROJECT SUBMITTED BY COLUMBIA GREEN TECHNOLOGIES INC., TUALATIN, ORE., WWW.COLUMBIAGREENROOF.COM
CALIFORNIA ACADEMY OF SCIENCES/ SAN FRANCISCO /
Located in Golden Gate Park, the California Academy of Sciences is a LEED for New Construction Platinum-rated museum; it was certified by the U.S. Green Building Council, Washington, D.C. The museum includes a 2 1/2-acre (1-hectare) vegetated roof that goes to a depth of 6 to 7 inches (152 to 179 mm). The roof’s diverse assemblage of nine indigenous plant species, including the city’s most concentrated area of native wildflowers, is a new component in an ecological corridor for the city’s wildlife. The design architect, Renzo Piano Building Workshop, Genova, Italy, recreated the topography of San Francisco on the building’s roof with four undulating, steeply sloped domed structures that mimic the nearby Twin Peaks. To solve the technical challenges of planting on a steep slope, the green-roof consultant, Rana Creek Living Architecture, Carmel Valley, Calif., worked with the design team to develop a built-up vegetated roof system. A biodegradable, reinforced, modular propagation tray made from rapidly renewable coconut-coir fibers provides water retention for the plants and helps hold the growing medium in place during plant establishment. The trays encourage plant growth from the use of a mycorrhizal biological inoculum that facilitates nutrient uptake and helps roots grow through the tray. About 27,500 square feet (2555 m2) of waterproofing material was used. The steep slopes act as natural ventilation and cooling. Fresh air, cooled by the vegetated surface, is funneled into the entry plaza where retractable skylights open to allow cool air to penetrate the building. The interior temperature is expected to be about 10 F (5.5 C) cooler than a building with a standard roof because of the thermal mass, surface moisture and insulation on the roof. The roof is anticipated to retain 2 million gallons (7.5 million L) of rainwater, preventing 70 percent of rainwater that falls on the roof to runoff. Any runoff is collected in basement-level cisterns and reused for roof irrigation. Stantec Architecture, San Francisco, served as the project architect, and SWA Group, San Francisco, served as the landscape architect. The implementation- landscape contractor was Jensen Corp., San Jose, Calif. Arup, San Francisco, served as the engineer.
PROJECT SUBMITTED BY AMERICAN HYDROTECH INC., CHICAGO, WWW.HYDROTECHUSA.COM
10 G ST. N.E. / WASHINGTON, D.C. /
Serving as a respite from the city and nearby Capitol Hill, the vegetated roof and labyrinth on the American Psychological Association’s building covers 3,600 square feet (334 m2) and cost $170,000. It has benches for reflection and provides a journal in which visitors can record and share their thoughts. The labyrinth, a circular walking path thought to enhance right-brain activity and provide a sanctuary for contemplation, is a seven-circle design, such as those found in ground-level parks. Under normal rainfall conditions, water and sewage from downtown Washington flow to a treatment plant and then into the Potomac River. During heavy storms, however, the sewer system becomes overloaded and polluted water and raw sewage run into local rivers and eventually the Chesapeake Bay. This vegetated roof and others like it help capture some of that runoff. The roof was funded by APA; Chesapeake Bay Foundation, Norfolk, Va.; TKF Foundation, Annapolis, Md.; and World Resources Institute, Washington, whose offices occupy the top 2 stories of the 8-story building.
PROJECT SUBMITTED BY WORLD RESOURCES INSTITUTE, WASHINGTON, D.C., WWW.WRI.ORG
909 WALNUT TOWER/ KANSAS CITY, MO. /
At 34 floors, this is the tallest apartment building in Missouri. Located in Kansas City’s financial district, it was built in 1931 as a bank and still offers office space today. An 8-story parking garage with a roof garden connects the 909 Walnut Tower and 929 Walnut building. The garden is approximately 17,000 square feet (1579 m2) and cost about $40 per square foot. Special growing media profiles are 6 inches (152 mm) for the lawn area and landscape beds. The garden provides community space; cabanas are included and there is a special area for dogs to exercise. The project won a 2008 Award of Excellence for Extensive Residential from Toronto-based Green Roofs for Healthy Cities. The Weitz Co., Des Moines, Iowa, served as the general contractor and construction manager. The garage architect was Stott & Associates Architects P.C., Ames, Iowa. The landscape, soil and irrigation contractor was H&R Lawn and Landscape, Stilwell, Kan. The waterproofing/roofing contractor was Delta Services, Kansas City, Kan.
PROJECT SUBMITTED BY GREEN ROOFS FOR HEALTHY CITIES, TORONTO, WWW.GREENROOFS.ORG
FEDERAL RESERVE BANK OF RICHMOND-CHARLOTTE BRANCH / CHARLOTTE, N.C /
The roof encompasses 83,000 square feet (7711 m2) with 63,000 square feet (5853 m2) of vegetated roof on multiple levels. Because the building is in downtown Charlotte, there were challenges with scheduling and delivery. Labor costs were reduced and installation eased by using a converted vacuum truck, which could blow the soil hundreds of feet to the rooftop. The entire roof is protected by an electric leak-detection system. There also is a drip-irrigation system when necessary. Plant media are drought-tolerant and consist primarily of sedum and other indigenous species. Roof Engineer Inc., Charlotte, was the architect and engineer, and Cyclone Roofing, a Tecta America Co., Indian Trail, N.C., served as the installer.
PROJECTED SUBMITTED BY TECTA AMERICA CORP., SKOKIE, ILL., WWW.TECTAAMERICA.COM