KÖSTER ECB Membranes are made of a mixture of Ethylene Copolymer and a special bitumen. A glass fiber mesh is embedded in the middle of the membrane to provide an especially high dimensional stability and resistance against shrinkage. KÖSTER ECB Membranes are watertight, chemically resistant, and resistant to stress cracking. KÖSTER ECB Membranes are UV-stable, resistant to aging, and microorganisms and can be applied directly to bituminous roofs. KÖSTER ECB U S Membranes are especially designed for the waterproofing of below ground building structures and are delivered with an aluminium foil laminated on top.