2.2. Roofs materials and experimental setup
As is illustrated in Fig. 2, there were two test rooms, and the dimensions were both 3 m × 3 m ×
2.7 m. The left one was covered by green roof, and the right one was common roof. The common roof
was made of foam sandwich panel (75 mm thick). Extensive green roof was consisted of 36
prefabricated greenery modules (Fig. 3) which was connected together by buckles, and the size of
every module was 50 cm × 50 cm × 7 cm (not including the canopy layer). The greenery module was
designed compactly, which com- bined plant layer, substrate layer, filtering membrane and drainage
layer together (Fig. 4). The plant was sedum linear (10 cm thick), which was very popular in
Shanghai district. The substrate was about 4 cm thick and was comprised of peat soil (60%),
powdered perlite (10%), vermiculite aggregate (20%) and organic fertilizer (10%). During the
experiment, the windows and doors of both
rooms were locked.