Yes, we advise that all natural stone tiles are sealed during installation. This is to ensure that grout residue has no way of penetrating the tiles and to give a long lasting defence against oil and water based stains during general use. We recommend Natural Stone & Timber Professional Stone Sealer and Universeal Rapid All-in-1 and that they are reapplied as directed on the label in accordance with the amount of usage and traffic that particular area receives.