Urbanscape® Drainage with buffer Q40 is a drainage and reservoir board (40 mm height) made from recycled polystyrene with excellent load-bearing capacity specifically designed for green roofs. The panels are perforated on one side to allow installation with the holes on the upper side for water retention. It is designed for flat and sloped green-roof systems with a slope of up to 20°. The drainage is made of high-quality plastic to ensure that the system is lighter and more compact in comparison with regular drainage layers. It complies with the FLL Guidelines for the Planning, Execution and Upkeep of Green-Roof Sites.