SOPRAJOINT is a SBS-modified bitumen expansion joint membrane for use in approved multi-ply membrane and flashing assemblies. The topside is surfaced with polyolefin burn-off film to optimize heat welding while the underside is surfaced with a foil bond breaker and a protective polyolefin release film that is removed during application. Soprajoint is composed of a proprietary formulation of elastomeric styrene-butadiene-styrene polymer modified bitumen and is reinforced with a tough, dimensionally stable non-woven polyester mat.