Moisture measurements in heritage masonries: A review of current methods and techniques

Measuring moisture content and its distribution in walls is a key factor in preventing detriment that water might cause. Although several techniques exist for the measurement of moisture content in buildings, most of them are not suitable to be used in cultural heritage constructions since they are based on procedures that can impair the valuable surfaces of the walls. Classical moisture measurement techniques, in fact, require sample taking, hole drilling, and probe insertion. All these actions might be more harmful than the consequences of possible water presence inside the masonry. For this reason, most of the research effort is directed toward developing completely noninvasive sensors (for example, superficial probes) and techniques (for example, remote sensing) to be used freely on surfaces that are also covered by paintings, without risking any damage. This paper presents an overview of current moisture measurement practices, examining nondestructive techniques and, in particular, noninvasive ones, for in-situ measurement of water content.