Surface finishes on historic buildings in the Salento Peninsular (Apulia, South Italy): early data

Many façades of historic buildings (churches and palazzos) in Lecce and the Salento bear lime washes, patinas, painted layers, etc of varying extent. While there are various anecdotal sources referring to standard practices for applying finishes to surfaces by using natural products, there is little or nothing in the way of documentation. IBAM has begun a study of the façades of historic buildings in the Salento, aimed at the characterization of stone surfaces, in order to identify the nature of the patinas, characterize the different types of finish, and discover what, if any, treatments have been carried out in the past and their function. This paper looks at several case studies. We are dealing here with buildings made of pietra leccese (a fine bio-calcarenite), on whose surfaces the presence of brown-ochre finishes of varying chromatic tonalities has been observed. The paper sets out the preliminary results of their mineralogical and chemical characterization carried out by means of optical microscopy with reflected and transmitted light, FT-IR, SEM-EDS on polished and thin sections and by Py-GCMS and GC-MS analyses on powders scraped off few samples.