Bostik Special Hardsurface Primer (SHP) is designed for all non-porous applications such as tiling over existing tiles. It is a one-part, modified acrylic dispersion primer and is easily applied by brush or roller. SHP provides excellent adhesion for screeding compounds and tile adhesives and is suitable for interior and exterior use. Also suitable for use over underfloor heated areas. In prolonged wet areas, tanking kits are recommended.