NON OF OUR PORCELAIN TILES REQUIRE ANY SEALANTS ETC . Porcelain tiles are made from finer clays than ceramic tiles thus when pressed and fired in the kilns they are much denser and harder than other floor or wall coverings .This makes them vertually impervious to water and the weather ,so they can be used inside or outside in the garden. The advantages are that they are more resistant to chips, chemicals and scratches and work well with underfloor heating .Because they are very hard porcelain can be even better choice than natural stone . MUCH LESS EXPENSIVE TO FIT AND FAR SIMPLER TO MAINTAIN .