A comprehensive study for moisture control in cultural heritage using non-destructive techniques

This article describes the use of non- or minimally destructive methods to study damp in San Juan Bautista Church at Talamanca de Jarama in the Spanish province of Madrid. The combination of Electrical Conductivity Meter (EC), Infrared Thermography (IR), RH/T monitoring by means of Data Loggers (DL) and Wireless Sensor Networks (WSN), Electrical Resistivity Tomography (ERT) and Ground-Penetrating Radar (GPR) techniques provided sub-surface and surface information. The respective findings and ranges of observation were inter-related to identify the decay associated with the damp and determine the advantages and drawbacks of each instrumental method. Electrical conductivity meters and infrared thermography deliver rough estimates of the extent of damp on wall surfaces, furnishing qualitative information on the areas where depth studies should be undertaken using techniques such as ERT or GPR or where long-term WSN monitoring sensors should be positioned to determine variability in a given number of points. When the purpose is to distinguish between areas with widely varying moisture contents, ERT is more precise. However, GPR proved to be the most accessible and efficient technique for studying the under-floor profiles.