Deterioration of stone artifacts and conservation treatments

The continuous alteration of the cultural heritage and the necessity to hand down to posterity the works created by man caused, along the centuries, the use of different products able to restore and preserve the stone materials. Since the antiquity many different products either organic or inorganic compounds, were used in the treatment of the stone materials, even if they were applied for different aims according to the fashion of the time. The present opinion on the preserbation of the cultural heritage currently followed in Italy requires the preservation and recovery of the stone artefacts as they came to us. There the use of suitable products, able to give back cohesion and durability to the decayed materials, is required. The aim of this paper is to review the restoration treatments of some historical buildings executed in the past 50 yeras. Our attention is particularly devoted both to the relationship between the characteristics of the stones and the restoration products, and to the effects that the tratments caused on the artefacts influencing their conservation state. The characteristics of rocks, such as composition, structure an porosity, in association with the stone exposition to the particular climatic o microclimatic conditions and its superficial working, have in fact a strong influence on the efficiency of the treatment products and on the durability of the restoration treatment.