There are many natural stones on the market. Depending on where and how the stone is used, will determine whether or not it needs to have a sealant applied to keep moisture from penetrating. Consult your installer, stone supplier or sealant representative for your specific stone type. The general rule of thumb, if you walk on it, or water can get to it, you should probably consider applying a sealant.
Here is an exception; one of the unique exterior stones we import is an authentic reclaimed cobble, “Historic European Cobblestone”. After 100 – 400 years of use, it’s already been exposed to all kinds of weather and dirt. It looks beautiful the way it is, and really nothing more than an occasional power wash is all that is needed to remove almost anything it will encounter – and its only going to get better with age.
If you have questions about your stone surface, let us know! We’d by happy to help!