Mould resistant wall & floor tile grout, Bostik J100 Smooth Finish Grout is a professional quality, mould resistant, cementitious polymer enhanced grout for walls and floors. Suitable for interior and exterior use with joints of 2mm to 12mm, it's resistant to efflorescence and formulated to provide a slump-free, smooth joint finish with easy clean off. It can be used with all types of ceramic and porcelain tiles, mosaics, natural stone and marble, and dries with a very hard finish.