State-of-the-art technology on conservation of ancient roofs with timber structure

The timber load bearing structures of the roofs are organized as a hierarchic articulation of members and structural units connected by joints and auxiliary beams to form structural systems. The authors list, for everyone of the cited levels, the techniques that can be considered obsolete as the indiscriminate replacements of members and units or, worst, of the entire system, the application of heavy steel profiles placed at the exterior or at the interior of the members and of the units or the invasive prostheses that stiffen the nodes and destroy their ductility. Considerations on the lack of appropriateness of these techniques are exposed. Today are available new techniques that, both obtained as adjustment of the old ones or based on completely new approaches, are inspired by conservation and repair criteria. Since they are based on interventions of minimal extent, they are able to ensure, within certain limits, respect for the original structure with the values they carry and rescue of the original configuration, materials and bond. The authors non acceptance of the practice of dismantling the structure, to some extent or entirely, in order to replace its damaged parts demands for working in situ thus allowing also the rescue of the original assembly.