Even and sealed surface SBS modified Kerabit bitumen membranes.
Rubber bitumen products maintain their elasticity even at temperatures down to -40 ºC Therefore, a well-made low-pitched ridge roof is a watertight and durable alternative, provided that it has at
least a double layer of bitumen-rubber membrane. As water will only run if there is a slight radient, there is no such thing as a totally flat roof — a flat roof is actually very low-pitched ridge roof.