APEX GREEN ROOFS - CAMBRIDGE, MA GREEN ROOF INSTALLATION
MIT - Massachusetts Institute of Technology
Green Roof Installation Details
Project Title: Sloan School of Management - MIT
Location: Cambridge, MA
Size: 7,000 sq ft
Planting Method: Extensive System/Cuttings(learn more)
Installation Date : Spring 2010
Press Release
May 4, 2010 Cambridge, MA. Apex Green Roofs, Inc. recently completed its first green roof installation of the 2010 construction season. The 7,000 square foot green roof is one of many green features of the new E62 building currently under construction at MIT's Sloan School of Management. Upon completion, the project will be submitted for LEED Silver Certification. The architects of the project are Moore Rubel Yudell Architects and Planners of Santa Monica, California and Bruner / Cott Associates of Cambridge, Massachusetts.
This green roof combines innovative technology with low maintenance plants to create a beautiful, functional landscape atop the building. It is estimated that the roof will retain approximately 115,000 gallons of stormwater a year. The vegetated system is built on top of a Sika Sarnafil PVC single-ply membrane. Directly above the membrane is a protection fabric, followed by a 25 mm drainage sheet made of recycled polypropylene. The drainage sheet not only allows for proper drainage but also retains 0.12 gallons of water per square foot, providing plants with water between rain events. Above the drainage layer is a 4 ounce non-woven separation fabric, which prevents growing media from clogging the drainage layer. The 4 inch layer of engineered growing media (consistent with FLL standards) is lightweight and allows for good drainage. In contrast to soil used in ground-level landscaping, the engineered growing media has a very low organic content and does not become compacted. These qualities both maximize the health of the plants and minimize nutrient runoff into the surrounding environment. Green roofs actually extend the life of the roof membrane by 2-3 times by reducing UV damage and impact from temperature variances throughout the year. As a precaution, the green roof system at the MIT Sloan School of Management includes a built-in place electronic leak detection system. Underneath the waterproofing membrane is a conductive grid. In the event of a leak, the source can be non-destructively located (accurate to within one foot). To prevent wind scour, the entire vegetated system is covered with a UV stable wind blanket, designed to meet Factory Mutual 1-35 guidelines for green roofs. In addition, permeable pavers located along the eaves provide a 16 inch buffer against wind along the leading edges of the roof surface. A portion of the roof is covered with pedestal pavers, separated from the vegetated section by a perforated aluminum edge.
The roof is planted with 11 varieties of Sedum, specially chosen to thrive in the harsh environment of an unirrigated green roof: Sedum acre 'Golden Carpet', Sedum album 'Green Ice', Sedum divergens, Sedum floriferum 'Weihenstephaner Gold', Sedum rupestre, Sedum rupestre 'Angelina', Sedum rupestre 'Green Spruce', Sedum sichotense, Sedum spurium 'Fuldaglut', Sedum spurium 'John Creech', and Sedum spurium 'Summer Glory'. All plants were distributed as cuttings, which dramatically reduces the labor as compared to planting individual plugs. Apex Green Roofs, Inc. provided a temporary battery-powered irrigation system that will provide the new cuttings with water while they grow roots and establish. After this initial establishment period, the green roof will not require any irrigation. Instead, all the water the plants need will come from natural rainfall. The plants are expected to fill in within the coming year--some species will even continue to grow throughout the cold New England winter! The green roof will be visible from offices and classrooms on the upper levels of the building. Throughout the year, building occupants can watch a dazzling showcase of colors, as the leaves change in color from green to vibrant shades of yellow, gold, and red. In addition, the green roof will reduce the volume of stormwater runoff from the building and provide a cooling effect in the summer. Apex Green Roofs, Inc. will perform regular maintenance visits during the first two years to ensure the success of the green roof system.
