Bostik Cempolay Ultra Strong is suitable for smoothing and levelling interior sub-floors prior to laying decorative floor coverings. It is also suitable for some exterior applications prior to laying ceramic tiles, slabs and natural stone and can also be used on domestic garage floors prior to over coating with a suitable floor paint. Bostik Cempolay Ultra Strong is ideal for smoothing/levelling of concrete, sand/cement screeds, and unglazed ceramic tile. It can be extended for filling holes and forming sloping screeds (5% downward gradients). Bostik Cempolay Ultra Strong is suitable for use with warm water underfloor heating systems provided a surface temperature of 27°C is not exceeded. The heating must be switched off at least 48 hours before and after the installation of the floor covering.