Moisture monitoring experience in the old town of Genoa (Italy).

The paper describes the monitoring process, which was conducted in an important and valuable religious building in Genoa: St Matteo Abbey. It has had serious problems with rising damp both in the hall, where the damage is particularly evident on the walls of the lateral aisles, and in the space below the crypt. In 2012, the Abbot decided to use an active system of wall dehumidification, which works with electromagnetic waves. The monitoring activities were carried out simultaneously and independently by Ecodry Italia and the University, under the supervision of both Superintendence (administrative architectural heritage body) and Curia (religious administrative body). During the days agreed for monitoring, measurements were taken independently by both parties in the same points with different equipment. There were four types of moisture measurements: environmental, superficial (Electrical Resistance method), sub-superficial (Electrical Capacitance method) and deep measurements (Gravimetric method). The paper includes the results of the moisture monitoring performed from 2012 to 2016. During the monitoring process, 6 survey campaigns were carried out, which, each time, investigated the same points and parameters to obtain values comparable to each other, in order to evaluate the actual effectiveness of the installed devices. The case study revealed critical issues regarding the structure of the Abbey that should have discouraged the choice of the dehumidification equipment and that inevitably reflected negatively on the outcome of the monitoring. It is therefore not possible to deduce, from such a complex case, a univocal result that proves that the installed dehumidification system is effectively decreasing the amount of moisture present in the walls of the Abbey of St Matteo, hall, and the room under the crypt.