Porous surfaces refer to surfaces that contain pores. A porous surface allows the passing through of water, liquid or vapor. Example of porous surfaces include untreated wood, ceramic tiles, marble, limestone, and slate.
It is important to protect your floors as porous surfaces are easily corroded and stains by spills. Even your common household cleaning detergent has the ability to corrode marble if it is acidic in nature. Acidic wine, coke and food items can also cause damages to your expensive floors.
When you protect your porous surfaces, what happens is that you add a layer of coating to the surface. This coating process is call impregnation.