If they are glazed ceramic tiles, they are not porous and do not require sealing. If they are unglazed ceramic tiles, they do need to be sealed. In both cases, we recommend that you seal the grout lines between the tiles. Use either the Grout, Tile & Stone Sealer – Quick Drying Aerosol or the Grout, Tile & Stone Sealer – Quick Drying Liquid. Any overspray to the surrounding glazed ceramic tiles is not a problem as Sure Seal® dries invisible. It will also help keep the tiles cleaner for easier maintenance.