The church of S. Marco (Florence, Italy), was begun by Silvestrini friars in the 14th century. Until 1436 it had a single nave and a roof supported by nine polychrome classical trusses. Michelozzo decided to eliminate the first truss and to replace the two subsequent trusses with large ones. It is to P.F. Silvani that the present wood ceiling is due, finished in 1725. In 1871 the first restoration work was carried out on the trusses. The reconstruction of the first using industrial planks was done in 1935. The last restoration was carried out by G. Morozzi in 1958. At present (1989), the roof displays alarming deterioration. The article presents studies carried out, with a proposal for restoration.