NDT for evaluation of volumetric water content in wood structures

The condition of the wood structure and its components should be carefully recorded before considering any action. The diagnosis of wood structures in heritage should precede any intervention. Is important to know preliminarily the construction and structural system, the decay condition and the causes. Furthermore, damage or structural failure should be considered. The diagnosis must be based principally on measurements of physical parameters using non-destructive testing (NDT), and if necessary on laboratory testing. Water is one of the principal causes of wood decay. In this study Groundpenetrating radar (GPR) and time domain reflectometry (TDR) was used to estimate the dielectric permittivity and successively the volumetric water content of several types of wood. An empirical relationship was found between the dielectric constant and volumetric water content. Results were applied to a case study: the Cathedral of Foggia.