The trend towards natural stone and unglazed tiles in the home has necessitated the need for good quality sealants. The sealant renders the porous tile or stone more resistant to staining and reduces the need for ongoing maintenance. However, a choice has to be made between penetrating and surface sealants. Penetrating sealants (also referred to as below-surface or impregnating sealants) have a low viscosity and provide protection just below the surface of the tile leaving little or no residue on the surface. Consequently, they do not significantly alter the surface appearance. Surface sealants (also referred to as coating or topical sealants) are designed to form a protective coating or film on the surface although some penetration does occur. The effect on the surface can vary from a very low sheen to a high gloss. Surface sealants are obviously subject to wear. The factors that need to be considered when choosing a sealant are discussed and their applications examined.