According to Bell (1993), the durability of a building stone is a measure of its ability to resist weathering and therefore retain its original size, shape and strength and appearance over an extensive period of time. As-built heritage materials resist decay differently, special attention is needed if constructions are intended to last for long periods of time. The specific resistant characteristic of each type of stone is determined by its petrophysical properties such as Density, Water absorption, Porosity accessible to water/Hg percentage, percentage of Microporosity etc.
