Thomas Rengstorf Associates undertook the unique challenge of designing an lightweight intensive greenroof upon a five story wood framed building at Dwell. To further challenge the design team no penetrations were allowed through the roof membrane. Thomas Rengstorf Associates was challenged in the technical aspects of this rooftop design that included a large gathering space for grilling and dining, a secluded sun deck and private retreat areas nestled amongst trees and shrubs. Active areas were planned over interior common area circulation spaces and above residential units washrooms and laundry rooms. Furnishing that could be easily lifted or rolled was selected for the rooftop spaces to minimize noise to the units below. A lightweight expanded shale was utilized for the soil media to minimize weights and allow adequate depth to support the plant material structurally. Metal screens and glass railings create microclimatic conditions for the sun deck area. The metal screen was designed with perforated panels and a large base plate to adequately resist wind.