There has always been debate about the need to seal marble and granite countertops with some believing it is necessary to protect the stone from stains. Others will say that most countertop materials are naturally impervious to staining and that protecting them from staining is not necessary. The marble Institute of America (MIA) takes the view that the right sealer can be beneficial in some instances, but only if a high quality sealant is used.
Most marble and granite countertops will reject stains and if they are cleaned appropriately following each use, there should be no issues. Sealants that have a strong resistance to water and oil can provide additional protection and the product should last between 10 and 15 years. However, if the homeowner takes the time to clean up spills and clean the surface properly, sealing the countertop will also serve to prevent any moisture from penetrating into the surface and will protect the stone from accumulating dirt and grime.
Another potential advantage is the presence of small fissures that can appear in stone countertops. They are often too small to see. Most manufacturers apply resin to the surfaces of marble and granite countertops when they are processed, but the appearance of fissures is still possible. Applying appropriate sealer can close those small fissures and make them impervious to moisture and will prevent the possible accumulation of food particles.
Remember that stone materials are a natural occurring product and there will be distinct marks on and in the surface. During manufacturing the process of smoothing and shining the stone may not eliminate what the industry refers to as “birth marks” in the stone’s flat surface. Consumers generally look for a countertop that is free of these distinguishing marks but processing can only do so much to eliminate them.
Resins are often used to fill in any small dips in the surface and manufacturing resins fill in any small openings that may be in the stone. Using sealers on the surface will not remove these birth marks and in many instances will not add to the water resistance of natural stone since it is already water and oil resistant. However, since this type of countertop will likely be the last one installed in the kitchen, the use of a quality sealant can increase the resistance for many years, usually outlasting the life of the home.
