For designers

Why elastomer bitumen on roofs?

Large roof areas, increased spans, lighter roof structures, efficient thermal insulation, increased life span requirement... Modern construction methods place tough demands on roofing materials. They have to withstand movements of the substructure, deformation of prefabricated components, temperature changes and stresses caused by ice formation in cold weather extremes. With efficient thermal insulation the roofing is subject to even greater temperature differences. The quality of roofing should not suffer even if installation is carried out in mid-winter.

KATEPAL elastomer bitumen roofing consists of one or more layers of elastomer bitumen membrane. Elastomer bitumen sheets are manufactured of styrene-butadiene-styrene (SBS) elastomer and bitumen bonded to polyester or glass felt. The waterproofing material of the sheet is crucial for keeping it weatherproof irrespective of the stresses it is subjected to. Thanks to its good stretch and elasticity properties SBS elastomer bitumen withstands high strain caused by movement even at very low temperatures. In this respect it is far superior to other bitumenbased weatherproofing materials (oxidized bitumen and APP modified bitumen). In Finland the lack of elastic properties at low temperatures has been a cause of serious problems in flat roofs.