First you should thoroughly clean the surface with an intensive cleaner. If the slippery surface was due to layer forming care products, the problem should now be solved. If the surface is still to slippery, you can use Lithofin Anti-Slip to “roughen” up the surface. The product removes microscopically small silicate particles from the stone / tile, thereby giving it more grip. Lithofin Anti-Slip is available in a convenient Set which includes all the equipment you will need to treat 6m².