Risk assessment for the conservation of Historic Buildings: new strategies and tools

The recent Cultural Heritage Code (2004) defines Conservation as planned, long-lasting process, passing previous concepts of “restoration”. Therefore, it led to innovate the research of testing and studying works of art, which where oriented to the “one shot in the building life”. According to the new perspective, achieving a preventive conservation makes the continuos application of good practices of maintenance necessary, supported by inspection/checking methods and structures to file the knowledge/assessment datas. In the most numerous cases, conservation means also developing planned activities to prevent damage. The turn of perspective from the passive protection of Cultural Heritage to the preventive mitigation of the cause of damage requires also to assess the risk factors due to the environment, location, use of the building, with the support of a preliminary diagnostics. Integrating diagnostic techniques for the early assessment of damages is useful to: 1) Mapping the presence of humidity, especially at severe ambient conditions, 2) Monitoring microclimate, by mapping colder surfaces (thermal bridges, different materials of coatings and masonry, etc) In addition, the analysis of risk factors inside and outside the buildings (environment, use of heating plants, presence of visitors, etc) have as a result the identification of specific microclimatic conditions and thermal-hygrometrical behaviours which are critical for the conservation of materials. Knowing such conditions, the further step of the plan of conservation is to draw the guide lines for the most effective removal of damage causes, without requiring a complete refurbishment or restoration of the building, control in time the results of preventive action, and to set the threshold values for the maintenance activities. The new trend of this applied research in the field of diagnostics for Cultural Heritage is to make the use of instruments on-site reliable, feasible and affordable. The obtained information is crucial to evaluate the risks and to plan the necessary actions for preventing further damages and loss of materials, with the results to warrant the permanence of the original and authentic features of the historic buildings.