Neoprene Sponge expansion joint filler is primarily used for masonry expansion joints for brick and block. Neoprene meets and exceeds all ASTM D-1056 specifications for Closed Cell Sponge Neoprene expansion joints in residential, commercial, and industrial applications. Neoprene Sponge helps prevent clogging of expansion joints with mortar and is the accepted material for brick and block expansion joint fillers. Neoprene Sponge can be custom cut for your job site needs and is available with or without PSA (pressure sensitive adhesive).