Non-destructive system for in-wall moisture assessment of cultural heritage buildings

Cultural heritage sites are exposed to several factors that cause their deterioration and degradation, namely moisture content. There are several destructive and non-destructive methods available to monitor moisture. However, destructive methods are avoided in cultural heritage to prevent surface damage, while non-destructive methods are limited to penetration capabilities. This study proposed geo-positioning of non-destructive moisture assessment based on microwave spectroscopy and close-range photogrammetry. The experimental data were collected at the Museum of King Jan III's Palace at Wilanów, Poland. The data was analysed using clustering algorithms (t-SNE, PCA, K-Means and Hierarchical), which demonstrated clear clusters. However, the microwave results did not fully align with the pin-type moisture data as the proposed microwave system was able to penetrate through the material, whereas the pin-type meter only measured the surface. Therefore, the microwave sensing approach provided more detailed moisture information of the measured material.