GREEN ROOFS

What is a green roof? Green roofs are plantings on the roof of a building Used in Europe for more than 25 years to control runoff volume, improve air and water quality, and promote energy conservation

Types of Green Roofs  Extensive  Intensive

Concerns on Everyone’s Mind  Costs – A built-in-place, extensive green roof can cost anywhere between $8 to $40 per square foot depending on a variety of factors  Weight – On average, an extensive green roof that is around 3 to 4 inches thick weights less than 17 pounds per square foot when saturated

Benefits  Reduce city “heat Island effect  Lengthen roof life by two to three times  Reduce storm-water runoff  Energy savings  Reduces noise  Neutralize acid rain effect  Aesthetically pleasing  Provides habitat

City “Heat Island” Effect  Higher surface and air temperatures caused by human built structures can result in extreme and sustained heat waves  Heat waves kill more people in the United States than all other natural disasters combined

City “Heat Island” Effect Causes:  Increased air conditioning use  Risks of power outages due to peak electricity demands  Worsens air quality by promoting ground- level ozone formation  Impairs water quality by heating storm water runoff, causing thermal shock for aquatic life

Green Roofs Reduce City “Heat Island” Effect  Plant transpiration and evaporation  Shading

Lengthen Roof Life  Insulates roof in the winter  Protects roof membrane from the elements  Protects roof membrane from UV radiation  Helps moderate the roofs temperature swings

Reduce Storm-water Runoff  Reducing Storm-water runoff is the best know benefit of green roofs  Can retain as much as 80% of the precipitation that falls on the green roof depending on soil depth and rainfall totals  Facility managers can reduce size or eliminate elaborate and expensive water management systems, another cost savings

Energy Savings  Green roofs moderate temperate swings and insulate buildings  Allow building to reduce size of air- conditioning equipment, another cost savings  Energy savings are significant on buildings that are one to two stories

Additional Benefits  Reduces Noise  Neutralize Acid Rain Effect  Aesthetically Pleasing  Provides Habitat

LEED Certification  Leadership in Energy and Environmental Design (LEED) Certification  U.S. Green Building Council  Green roofs can help a facility earn as many as 7 to 23 points towards LEED certification

Green Roof Contribution to LEED  Sustainable Sites: –Reduced Site Disturbance –Storm-water Management –Heat Island Effect  Water Efficiency: –Reduced Site Disturbance

Green Roof Contribution to LEED  Energy and Atmosphere –Optimize Energy Performance  Materials and Resources –Building Reuse –Recycled Content –Regional Materials –Rapid Renewable Materials

Green Roof Contribution to LEED  Innovation and Design Process

Green Roof Examples – Atlanta Area  Bio-Chemistry Connector, Emory (1995)  Zoo Atlanta’s Conservation Action Resources Center (1997)  3TEN HauStudio (2001)  Atlanta City Hall Pilot Green Roof (2003)  Woodward Academy Middle School Art Building (2004)  Gwinnett County Environmental & Heritage Center (2006)  Sweetwater Creek State Park Interpretative Center (2006)

Green Roof Examples – Federal Government  Hastings Keith Federal Office Building, New Bedford, MA – GSA (2004)  Center for Urban Ecology, Washington, DC – National Parks Service (2004)  McCormack Post Office and Courthouse, Boston, MA – EPA Region 1 (planned)  Laboratory Annex 2, Cincinnati, OH – EPA (planned)  EPA’s Region 8 Office, Denver, CO (2007)  EPA Headquarters, Arlington, VA (2006)

Useful Websites  EPA Green Buildings  Atlanta Area Green Roofs –  US Green Building Council Web Site –  Heat Island Effect – enroofs.html enroofs.html enroofs.html

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