M.I.T. Sloan School of Management
Apex Green Roof Installation Year: 2011
Owner: MIT Sloan School of Management
Location: Cambridge M.A.
Building Type: Institutional
Architect: Moore, Rubel Yudell Architects and Planners of Santa Monica, California and Bruner / Cott Associates of Cambridge, Massachusetts
Waterproofing Membrane Contractor:
The 7,000 square foot green roof is one of many green features of the E62 building at MIT's Sloan School of Management. The architects of the project are Moore Rubel Yudell Architects and Planners of Santa Monica, California and Bruner / Cott Associates of Cambridge, Massachusetts.
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.