If your tiles are installed in direct sunlight with no shade cover, I wouldn’t recommend applying sealer. But if your tile is covered by a courtyard, an awning or heavy foliage, then applying a sealer can add a nice sheen to the appearance of your tile.
Using a penetrating sealer will make the tiles easier to clean, although it can make them a bit slicker. I like a product called Lock Out. Combine it with color grout seals to protect the grout and block debris.
Saltillo is a clay tile, and, left unsealed, is susceptible to staining and to efflorescence, that fuzzy white powder that shows up after a hard rain or if your sprinkler system waters the tile too often. Before you apply a sealant, stop the efflorescence. To stop efflorescence, you must eliminate the water source.
Adjust your sprinkler system or install a downspout to keep water from flowing onto the patio. Once the water source has been eliminated, the white stains can be scrubbed with a mild acid wash.
It’s futile to go through the time or expense to seal, recoat or otherwise try to do away with efflorescence without first eliminating the water source.
