Medieval Sardinian castles. Transdisciplinary approach for the definition of typologies, masonries and materials

The present study stems from the awareness that researches on traditional masonry techniques in Sardinia, and particularly those aimed at dating historical architectures, are insufficient when compared to the studies on other Italian cultural areas starting at the end of the 20th century. Over the last decade, the Chair of Restoration in the University of Cagliari has carried out a research project focused on the archaeometric investigation of traditional masonries (12th-19th centuries). This paper refers to the medieval Sardinian fortified systems (12th-15th centuries). The purpose of this research is to define chrono-typological references, and easily to recognize, date and preserve the so-called minor buildings, which are not philologically dated unlike the examined ones. The investigation protocol, specific for local peculiarities and based on a transdisciplinary approach, started with the indirect analysis. A direct survey of the structures was further carried out through photographic, architecture and material assessments, with non-destructive diagnostic techniques. The creation of a Geo-Topographic Database and a WebGIS were essential to archive and manage the collected information. These tools allowed cross-referencing the archival and archaeometric data, very useful in facilitating the definition of chronotypes. This method allowed gaining knowledge of local historical masonries, identifying important references in dating buildings. In particular, architectures of ancient Sardinian villages often undergo improper interventions regardless their historical and cultural values. Consequently, dating becomes an essential tool to protect and preserve them. A successful planning project on historical buildings should be based on conservation criteria, for which recognising the specific technology of historical materials is fundamental. Also, this study offers a better understanding of the entire system, whose current fragmentation - as a result of the absence of conservation actions, of abandonment, demolition, improper reuse and reconstructions - proves the need of identifying its values and critical issues, essential for a project aimed at the successful protection and enhancement of its components.