Large span timber roofs in Italy between XVI and XIX century

The object of this paper is to depict some characters of long span roofs in Italy between XVI and early XIX century, with the aim of highlighting the transregional and transnational transmission of knowledge over this period. The article follows other publications of the past years on this topic and it is based on document analy-sis and building survey; it uses the analysis of some manuals, and publications of the time. Different solutions in Italian regions are considered and compared, in particular the roof structures of some churches in Bologna; this area is particularly important because it is placed between Rome and the northern regions of Veneto and Lombardy. Until the beginning of the XIX century the design and construction of this kind of roofs was pri-marily based on direct experience and practice. Starting from that period the design and the verification of trusses started to derive from the theories of the new born Building Science. The aim of the paper is to bring together part of the previous literature on this topic, which is mainly focused on specific buildings and specific regions, trying to highlight cultural ties, influences, technical references and derivations between regions.