Critical Analysis of Restoration Practices: The Case of San Pietro Barisano’s Church in Matera

The city of Matera has an ancient connection with the calcarenitic rock, a fundamental material for understanding its architectural history. This limestone rock is easily workable but vulnerable to various types of degradation so it has often been subjected to conservative interventions that have not always achieved the desired results. Instead, they have sometimes worsened the initial conditions by altering the building’s surfaces. Starting from the 1990s, the ancient district named “Sassi” has been undergoing restoration works and on-site experimentations of new products and techniques. Configuring itself as a laboratory of experimental restoration practices, it is well suited for an analysis aimed at identifying the best practices currently available in the field of architectural heritage conservation. Despite all the interventions were carried out in a uncoordinated manner by intervening “for emergencies” or on individual issues, the analysis of the interventions, products and techniques used to counteract different types of degradation and preserve the conservation status of the building has made it possible to gather valuable information to identify a broader standard for planned and preventive maintenance of the architectural heritage. The paper is focused on the critical analysis of interventions carried out on the Church of San Pietro Barisano, an important historical and architectural landmark of the city, founded in the 12th century and characterized by several construction phases. After a long period of abandonment, it has suffered significant surface deterioration due to environmental and construction factors, as well as the presence of rising damp in the walls. This analysis is part of a research project that aims at developing a digital protocol of good practices for architectural heritage conservation by promoting preventive and predictive maintenance. The results of the investigation underlines the key-role of pre and post intervention diagnostics.