We usually think of porcelain tiles as having a shiny, glassy surface, but that’s actually the glaze that’s used on many types of porcelain. The porcelain itself is a clay-based product, and has a flat, earthy look if it isn’t glazed. Unglazed porcelain is an interesting look for a floor, but it will absorb stains if you don’t seal the surface in some way. Liquid tile sealers will seal the tile without putting a shine on it. The sealer should be installed in conjunction with the initial grouting process.
Install the porcelain floor tiles in mortar, with the appropriate spacing between them. Let the mortar set for a day.
Vacuum out the spaces between the tiles, using a vacuum hose.
Brush on a layer of liquid tile sealer with a paint brush, covering just the flat top surface of the tile and not the exposed edges inside the spaces between.
Let the sealer dry for three or four hours, then apply a second layer in the same manner. Let it dry for another three or four hours.
Grout the floor starting in the far corner from the entrance. Spread the grout over the surface with a grout trowel, using the long edge of the trowel to scrape the grout off the surface while forcing it into the lines between the tiles. Wipe up the excess grout with a damp sponge.
Let the grout set for at least four days. Brush on a third layer of sealer, this time covering the grout as well as the tiles. Let the sealer set for a day before walking on the floor.