Look up! Manchester's first "green roof"
now sits on top of City Hall's Connector building.
This UNH Cooperative Extension Initiative combines new technology with plants to deliver many benefits to the building below and to our overall urban environment.
Most rain that hits a conventional commercial roof flows off, carrying with it heat and particles. As the runoff hits the ground below, it picks up more pollutants: gasoline, oil, antifreeze, sand, and heavy metals that end up in local streams and rivers.
As the amount and velocity of rain increases, stormwater runoff can cause flooding, and overload the wastewater treatment plant, which then dumps untreated sewage directly into the Merrimack River.
The green roof absorbs up to 95% of a 1-inch rainfall, allowing it to percolate slowly through the plants and soil. Much of the water evaporates and what runs off is delayed, giving sewer systems time to recover.
Plants on the Green Roof
The planting beds behind this sign contain the same plants growing on the roof, many of which can be found in the gardens around town.
Benefits of a Green Roof
The plants and soils in a green roof serve many functions, which include:
· Reducing the energy needed to heat and cool the building below.
· Saving money by
extending the life of the original roof.
· Absorbing noise.
· Lessening the risk of flooding and overflowing sewers.
· Providing habitat for butterflies and other pollinators.
· Filtering air pollutants, improving air quality.
Installing the Green Roof
The GreenGrid System uses 4-inch deep recycled plastic containers filled with a lightweight growing mix and planted with perennial plants that thrive in hot, dry, and windy rooftop conditions.
Installation took two hours. After covering the original asphalt roof with a slip sheet, the installation team lifted the pre-planted containers into place.
Unlike some green-roof systems, the GreenGrid System doesn't require additional roof construction or design.
· For more information about Manchester's green roof, including updates on temperature monitoring and pollutants absorbed by plants, go to: www.ManchesterNH.gov/CityGov/dpw/EPD/greenroof.html [does not work]
· For specific information on the GreenGrid System used here, go to www.greengridroofs.com
· For more information on green roofs, go to http://extension.unh.edu/FHGEC/greenroof.htm [does not work]
No Manchester tax dollars were used for this green-roof project. All funding came from grants and private sponsors:
· UNH Cooperative Extension in partnership with the N.H. Division of Forests and Lands and USDA Forest Service
· TFMoran Inc.
· McLane Law Firm
· Manchester Development Corporation
· Lavallee Brensinger Architects Fund of the N.H. Charitable Foundation, Manchester Region
· Weston Solutions, Inc.
· N.H. Dept. of Environmental Services
· Anonymous Fund of the N.H. Charitable Foundation
· Breathe NH
· SEPP - Enterprise Fund, administered by the City of Manchester Environmental Protection Division
· City of Manchester
· Intown Manchester
· Greater Manchester Chamber of Commerce
· UNH Manchester
[Photos of various green roof plants]