CHARACTERISTIC WEATHERING TYPES ON THE FACADES OF BASILICA OF SAN GAVINO AT SARDINIA.

The stone material used in the construction of many ancient monuments of cultural heritage decayed during centuries losing its properties. Traditionally such stone material was gradually replaced with the stone material of similar quality. However, the preliminary studies of the replacing material are carried out rarely. Therefore, the information on the reasons provoking the decay of the material is lacking; yet, it would be necessary to obtain such data in order to evaluate the necessary reconstruction work and in the case of larger monuments - to choose the most appropriate conservation strategy. Our study was carried out in several medieval monuments located on the islands of the Mediterranean region and in most details - the basilica of San Gavino at Sardinia. The studies allowed us to identify at least six different stone material weathering types with five different weathering intensities. Additionally, certain genetic order of these weathering types was noted - the sequence how the stone material has weathered and lost its properties. This allowed us to elaborate the stone material decay monitoring system, providing an opportunity to develop well timed measures for monument's preservation. [ABSTRACT FROM AUTHOR]