the vaulted roof of San Vittore in Milan: an unusual sixteenth century construction

San Vittore al Corpo in Milan, one of the most singular and intact 16th century religious buildings in the city, is known for the long disputes on the role of the architects – Galeazzo Alessi, Martino Bassi, Vincenzo Seregni, Pellegrino Pellegrini – whose names recur in the documents of a construction site which lasted almost half a century, without today’s church showing an evident lack of homogeneity. The constructive aspects have not been considered, although the estimates drew up at that time – unusual in Milan – are very detailed and correspond essentially with the existing building. The transept and the presbytery are covered by a thin brick vault, onto which the roof tiles rest directly. It repeats the vault underneath, pierced by deep webs, between reinforcement arches which emerge both in the intrados and the extrados. The exceptional case of Sant’Andrea in Mantova, in which the roofing rests directly upon the vault of the nave, gives way here to a variation which has some rare parallels in the case of terrace roofs. Moreover, the deep pillars which separate the nave from the aisles extend into the attic and connect with the outer walls, acting as buttresses for the large barrel vault with shallow lacunars, made of bricks: the transversal section apparently looks round but is actually parabolic, and its width decreases from the impost to the keystone. The trusses of the roof rest on the internal buttresses and channel a relevant vertical load onto them: by avoiding the more common solution of buttresses which rise above the walls of the chapels it is possible to build a continuous roof which ensures better maintenance. By surveying the placement of the bricks, through the thermography of the intrados and the survey of the extrados, and by rereading the 16th century documents, it is possible to make hypotheses on the building methods and it will be possible to clarify why apparently similar vaults are substantially different with regard to their texture and structural behaviour. The comparison with other contemporary Milanese and Lombard construction sites, through bibliography and direct enquiry, contributes to convey the larger framework of knowledge and concrete cases known by the architects who worked at San Vittore. The objective is to gradually fill a gap in the history of construction in the Modern Age: the Lombard workers operated within a larger European framework, thanks to their recognised technical skills, especially where brick construction prevails.