Cement tiles are hand-made using the same basic process that was invented in the late 19th century. Sealers didn’t emerge on the market until the 1960s and weren’t commonly used until a decade later. Before sealers, cement tiles were protected from staining with an application of kerosene and paste wax.
Cement tile manufacturers today recommend a high quality penetrating stone and tile sealer for any installation. However, we have had successful installations without sealers where staining or liquid absorption was not a concern. Furthermore, with the right sealer, cement tile can be installed in pools as a decorative sideboard.
Because cement (or concrete) tiles are porous like natural stone it’s generally a good idea to seal them so they are more resistant to staining. A sealer is a liquid applied to cement tiles (and porous natural stones) to help prevent staining from water and oils. In effect, a sealer reduces the natural absorbency of a stone or concrete material.