La tecnica costruttiva delle scale a chiocciola nel Medioevo. Scale a volta gettata, a gradino portante ed a Vis de Saint-Gilles

Medieval construction techniques of spiral staircases: cast vaulted staircases, self-supporting steps, and vis de Saint-Gilles This paper analyses the constructive history of spiral staircases. The structures are classified into three different main categories: stairs carried by vaults, self-supporting steps, and vis de SaintGilles. Several staircases are studied for each typology in terms of their technology, their differences, advantages, and disadvantages. This paper adds to the literature on dating buildings through the stairs. Some examples analysed in this paper are the case studies of Cosenza’s cathedral and Castel Maniace in Siracusa.