Solar loading thermography for architectural heritage surveys: plumb the depth by looking at the façade

The paper is centered on two case-studies in which the role of the sun as thermal stimulus is discussed working with the infrared thermography (IRT) technique. The first case-study is based on Santa Maria di Collemaggio Church in L’Aquila (Italy), initially built in the second half of the XIII century. The second case-study talks about a masterpiece of Venetian Gothic, i.e., Palazzo Ducale in Venice (Italy). In both cases, the striking jewel-box effect of the facades is due to a pattern of blocks of alternating pink and white stones. The facades and one lateral side of the Church constructed by using the masonry local system named, “apparecchio aquilano” have been inspected. Subsurface anomalies such as cracks, buried structures, humidity and metal reinforcements can be visualized exploiting the solar cycle