2. Methodology for diagnosing deterioration

According to the practical guide issued by the Direction Générale des Patrimoines (French Heritage Agency) , the diagnosis "enables us to establish a detailed report on the current state of the property and to determine the nature and causes of all alterations and disorders, as well as the resulting conclusions. Diagnosis is based on observation, investigation and historical analysis".

There are therefore three diagnostic scales:

• Diagnosis, using observation and monitoring methods, i.e. the findings ;...