When we talk about closing a surface we normally mean an impenetrable barrier used indirectly or painted on. For example tiled floors are often covered to give added safety and make them shine. To do this some layers of emulsion polish are applied allowed to dry and are placed on the area. This gives provide floor protection and closes the floor off to water and chemical attack. Additional areas for example timber tend to be covered with a finish of a polyurethane product such as epoxy. This adds strength to the surface and protects it. Other permeable surfaces, such as concrete, can be sealed using a layer that sits on the area acting as a barrier to penetrative agents and physical defense. The waterproofing of natural stone for example limestone, granite, marble and record is hardly same. Organic stone consists of crystals that interlock together. The genuine nutrients that are not absent as crystals in the rock give it striations and its colour. However there are spaces between the crystal and small these spaces are and the more the deposits have now been condensed the permeable the rock is together. So these spaces will determine the porosity of the rock….