Cement-based grout suitable for ceramic, porcelain and mosaic tiles on joints up to 6mm. It is also suitable for use on stable timber floors and underfloor heating. Pot life is 2 hours, and it sets in approximately 24 hours. This grout is for interior and exterior use. Mapei Flexible Wall & Floor Grout 2.5kg in Cement Grey. This 2.5kg wall & floor grout in grey is suitable for use with underfloor heating, timber floors, ceramic tiles, concrete, natural stone, plaster, plasterboard, porcelain & timber. Simply apply and leave for 24 hours to dry. Each pack covers up to 8 m² on average.