ALSAN RS Paste is used to fill small cracks, depressions and voids in a non traffic bearing horizontal or vertical substrates after priming & prior to application of ALSAN RS systems. ALSAN RS Paste can also be used to smooth out laps on ALSAN RS 230 and ALSAN RS 260 membranes when applying aesthetic top coats or surfacing. ALSAN RS Paste is a rapid-setting, proprietary formulation polymethyl methacrylate heavy paste.