The roof’s steel support system is designed for a 62 lbs./s.f. live-load capacity but real loads are less due to use of a lightweight expanded-shale aggregate growing medium.
The roof features both intensive and extensive areas and includes plant species carefully selected to ensure they could withstand the conditions on the roof, which are hotter, drier, and windier than on the ground. The extensive areas have a 4″ soil layer and are planted with nine species of sedums. The intensive areas, which have between 4″ and 9″ of soil with higher organic matter content, are planted with a variety of native perennials and shrubs.
A unique feature of WSSI’s green roof is the two wetland pods. Each pod was created from a loop of 6″ flexible HDPE pipe, a pond liner, and thick, impermeable soil. The pods are kept wet by individual moisture sensors and drip irrigation systems. During the first growing season in 2006, the bull rush grew nearly 6’ tall. The green roof is supported almost entirely by direct rainfall.
Contact us for more information including roof deck details, grading plans, section views, planting plans, and the plant list.