Debobase 3.5 mm Special is a flexible waterproof membrane consisting of a special mixture of elastomere modified oxidised bitumen, and reinforced with a layer of non-woven polyester of min. 200 g/m². The upper surface is finished with 1 to 2 mm calibrated sand. The under surface is finished with a polyethylene foil of 12 micron thickness. This roofing can be applied by torch.