Mapei Keraquick S1 in Grey is a quick-setting, flexible, cementitious adhesive for ceramic, porcelain and natural stone tiles, glass tiles and mosaics. Suitable for interior and exterior use, this tile adhesive can be used to bond tiles to cement-based screeds and renders, concrete, plywood overlaid floors, existing unglazed ceramic floor tiles, gypsum plaster, plasterboard and tilebacker boards. It can also be used for spot bonding insulation materials, such as expanded and extruded polystyrene panels, gypsum boards, rock and glass wool, aerated concrete blocks and sound-deadening panels.