The role of non-invasive diagnostic investigations in the conservation of fortified cultural heritage: methodology and a case study

This topic explores recent developments in the use of diagnostic tools in conservation, particularly in the investigation of the surfaces of fortified architecture through the use of thermography. This investigation is not limited to the analysis phase alone, but also plays a fundamental role in the post-restoration phase.Thermography, a non-invasive analysis of architectural surfaces, is not only a preparatory activity, but is also aimed at critically understanding buildings and their state of conservation. It is a useful support in the preventive and planned conservation phases for site management. This method of architectural investigation originated in the 1980s, when the Central Institute for Restoration (Istituto Centrale per il Restauro) began to analyse the effects of solar radiation on the dome of the church of Santa Maria del Fiore in Florence. Its use in studying the causes of deterioration in historic buildings has been the subject of numerous publications. It has recently been used with good results in a research project studying the stratigraphy of both plastered and un-plastered fortified buildings. The response of various materials to infrared radiation allows for the identification of stratigraphic levels in plastered surfaces. The integrated use of thermography with other diagnostic techniques can also be useful for analysing the degradation patterns of historic heritage. This paper presents a significant case study, conducted both in the preliminary study of fortified architecture and in the analysis of the restoration work carried out. This study verifies the design choices, the state of conservation of the plaster and restoration mortars, and the responses over time, depending on the materials used. It also outlines the timeframes within which thermographic investigation is most effective. Thus, thermography enhances maintenance plans, demonstrating how its calibrated use is also beneficial in economic terms.