Characterisation of surface finishes on ancient historical buildings in Salento (Southern Italy): An integrated analytical approach to establish the secrets of artisans

Abstract Finishing, i.e. the application of hydrophobic materials is an important treatment for the conservation of stone surfaces and the protection of Cultural Heritage decay. The practice of covering the stone facades of the buildings was also used in the past in Lecce (Puglia, Italy). Historical and oral sources report that natural waterproofing agents were used for aesthetic, protective, hygienic and conservative purposes: walnut oil, caprine, ovine or bovine milk, leaf of the Opuntia ficus-indica , beeswax, and bulb of the Drimia maritima plant. In the present work, it was carried out the first historically accurate reproduction of the ancient finishing techniques used on Lecce historic buildings for scientific research: test specimens of local stones ( pietra leccese and carparo ), treated according to ancient recipes and subjected to natural and artificial aging, have been studied and the physical and chemical modifications determined. This study permitted to gain knowledge about the ancient finishing techniques and their degradation.