Coating’s influence on water vapour permeability of porous stones typically used in cultural heritage of Mediterranean area: Experimental tests and model controlling procedure

tWater vapour flux into the porous microstructure represents a crucial factor capable of influencingthe degradation of porous materials. This fact is of utmost importance especially considering materialsinstalled in cultural heritage. The necessity to preserve stone artworks pushes to perform surface pro-tective coatings that create an intermediate sacrificial layer between stone and the environment. Highhydrophobicity and high permeability of water vapour must be one of the most important requirements ofa protective film. These features depend upon the nature of coatings as well as the porous microstructures.In order to control coatings’ effects and their influence on final water vapour permeability (ı) properties,a new modelling procedure has been proposed. The study is conducted on a porous limestone, namelyPietra Leccese, which is being largely used for historical constructions in Mediterranean. The averageexperimental water vapour permeability ıexpis 4.83 × 10−4and 3.86 × 10−4(g/m d Pa) respectively foruntreated and treated PL stone, while the average model prediction ıIFUis 4.87 × 10−4and 3.77 × 10−4(g/m d Pa) respectively for untreated and treated PL stone. The good agreement between experimen-tal and calculated data shows that the proposed modelling procedure could represent a good tool fordesigning and controlling protection activity on cultural heritage.