Target Center Green Roof is Complete
2.5 acre green roof is largest in Minnesota
September 15, 2009 (MINNEAPOLIS) — The City of Minneapolis celebrated the greening of the Target Center roof at a completion celebration today on top of the arena. The roof is the largest green roof in Minnesota and, at the time of design, the fifth largest green roof in the United States. The Target Center is also the first arena in North America to install a green roof.
"With the redesign of the Target Center roof, Minneapolis has again proven that sustainability and economic progress can go hand in hand," said Minneapolis Mayor R.T. Rybak. "Green initiatives such as this will not only improve the environment for city residents, but continue to cast Minneapolis as a leader when it comes to green industry."
"We lead best by example," said Council Member Lisa Goodman, "and building one of the nation’s largest green roofs will allow us to ask others to do the same." "For years we have worked to reduce the City’s negative effect on the Mississippi’s stormwater quality," said Barbara A. Johnson, City Council President. "This is a big step forward, built by hard-working Minneapolis citizens and area laborers."
Benefits of the Green Roof
Green roofs provide ecological benefits by reducing the negative effects of hard surfaces, like traditional roofs, on stormwater quality, volume, rate, and temperature on the receiving waterbody, in this case, the Mississippi River. It is estimated the green roof will capture one million gallons of stormwater annually, preventing drainage into the Mississippi River.
The green roof will also help in mitigating the heat island effect in downtown Minneapolis by reducing the roof’s temperature by as much as 80 degrees
Fahrenheit.
There are opportunities, under public contract, to provide jobs for Minneapolis residents; 75% of the workers who worked on the installation of the roof were Minneapolis residents. Twenty of the workers were graduates of training programs at Summit Academy OIC.
Construction of the Vegetated Roof
Pre-grown mats of sedum plants create the base of the green roof system. Mats were laid on a state-of-the-art waterproofing membrane which includes a leak detection system called Electro Field Vector Mapping (EFVM). The membrane will help withstand constant dampness, high alkalinity, and exposure to plant roots, fungi, and bacterial organisms as well as varying hydrostatic pressures.
The green roof features a 1.75" growing zone in the center of the main arena roof structure and a deeper 2.5" growing zone around the perimeter where the structural capacity is greater to maximize storm water retention and plant vigor. The roof uses the pre-grown mats as the base of the green roof system and contains a variety of Sedums and Minnesota prairie plants, including Columbine, Lanceleaf Coreopsis, Wild Strawberry, Dotted Blazing-Star, and Lupine. It includes lupines to target the Karner Blue Butterfly, a federally listed endangered butterfly that needs lupines to survive. Prairie seed was also used to increase long-term resilience of the green roof.
More than 11 miles of sustainable, water-efficient irrigation lines were installed and 14,000 cement pavers for firebreaks and roof protection laid.
While the project called for 50% recycling of materials, the Tecta team set its own goal of recycling 100% of the old roof, resulting in an estimated 450 tons of existing rock and 590 tons of existing pavers, 140 tons of existing roofing membrane and more than 60 truckloads of existing roof insulation.
Minneapolis as an Environmentally-Friendly City
Minneapolis is recognized as one of the most environmentally friendly cities in the country. Target Center’s green roof is just one of many examples of how City government has led by example and taken advantage of the benefits of being green.
City Hall is also home to a green roof, and several Public Works and Fire Department facilities use solar arrays to help generate power. The City has also adopted a Leadership in Energy and Environmental Design (LEED) Silver standards, which require new or significantly renovated City facilities to meet some of the highest standards for sustainability in their planning, design, construction and commissioning. A new ordinance limits vehicle idling in the city to reduce emissions, and Minneapolis is the first U.S. city to require higher fuel efficiency for taxis. The City’s innovative stormwater utility program has dramatically increased the use of rain gardens and other effective practices to protect our lakes from stormwater runoff. Minneapolis has also created a unique program to provide microgrants to community organizations to support their efforts to fight climate change.
Since Minneapolis sustainability initiative was launched in 2003, City leaders have developed a series of 25 indicators, including things like air quality, bike paths, green jobs, and tree cover. Each indicator includes specific numeric targets, which serve as goals for Minneapolis to reach in the coming years. To learn more about Minneapolis sustainability efforts, visit Sustainability Initiatives.
The green roof design team includes Leo A Daly, Kestrel Design Group, and Inspec; locally-operated Stock Roofing, a Tecta America company, is replacing all of the roofs on the Target Center and installing the extensive green roof.
The installation and ongoing maintenance of the green roof is the last stage of a necessary roof replacement project that also includes replacing all 29 smaller roofs on five levels. The cost of roof replacement for all 30 roofs is $5.32 million and is paid for using a set-aside capital fund for improvements.
About Summit Academy OIC
Located in the Heritage Park neighborhood of North Minneapolis, Summit Academy
OIC is the only community-based vocational training and job placement program in
North Minneapolis. Summit Academy OIC assists individuals in developing their ability to earn and to become contributing citizens in their community; supports the development of self-sufficiency in every person, regardless of background, economic status, or level of ability; strengthens the community by preparing individuals to assume their roles as workers, parents, and citizens.
About LEO A DALY
LEO A DALY is an international architecture, planning, engineering, interior design and program management firm with 1100 professionals in 30 offices worldwide. The firm has a 40-year history in designing sustainable buildings including the award winning Gold LEED® regional headquarters for the National Park Service in Omaha,
NE, and is currently designing a platinum LEED® building in Doha, Qatar. LEO A
DALY's Minneapolis office comprises 134 professionals and it is currently completing
12 sustainable buildings, aimed at Silver LEED for the U.S. Army at Fort Carson near
Colorado Springs.
About Kestrel Design Group
The Kestrel Design Group is a Minneapolis-based, sustainable landscape architecture firm specializing in green roofs, living walls, storm water and urban trees and sustainable site solutions. An emerging leader in both green roof technology and tree cell technology, it co-authored Minnesota's Sustainable Building Guidelines and The Minnesota Soil Bioengineering Handbook. Its recent green roof projects include Minneapolis City Hall, the Minneapolis Central Library, Edgewater Condominiums and the Green Institute/Phillips Eco-Enterprise Center.
About Inspec
INSPEC, Inc. is an engineering/architectural firm specializing in roof, exterior wall, pavement and waterproofing design, construction observation, and management services. It employs more than 65 engineers, architects, project managers, technicians, and office support in offices located in Minneapolis, Milwaukee, and
Chicago. Inspec has been providing sustainable roofing, waterproofing, and other building envelope solutions for over 35 years. The firm has completed over 40 projects in which the waterproofing membrane has a vegetated or otherwise landscaped overburden.
About Stock Roofing, a Tecta America Company
The Stock Roofing Company, LLC. was founded in 1987 Warren Stock, a small business owner and operator in Minneapolis, Minnesota. For nearly twenty years,
Stock Roofing has grown in capacity and capability to meet the residential and commercial roofing needs of the Twin Cities metropolitan and surrounding areas. In 2003, Stock Roofing Company, LLC. joined Tecta America Corp. Stock Roofing has installed the most square footage of any other green roof contractor in the State,
About Tecta America Corp.
Tecta America Corp., headquartered in Skokie, IL, is the largest commercial roofing company in the U.S. and provides roofing solutions nationwide with over 50 locations and more than 3,500 employees. Services include roof installation, roof replacement, new construction, disaster response, repair, restoration, maintenance, full service national roofing management and, through its Tecta ES [Environmental Solutions] division, green roof systems, photovoltaic systems, and day lighting systems. Tecta is also the largest green roof contractor in the nation.
Published Sep. 15, 2009