Moisture is an essential factor in rock weathering. Therefore, the exact determination of the water content of rock material is important for the building industry as well as for science. So far there is no measuring method available which is practicable for both areas and which provides reliable moisture data. For this reason, new capacitive sensors for measuring rock moisture have been developed at the Institute of Geography and Spatial Research at the University of Graz. They are based on the principle of a plate capacitor. The capacitance C of such a capacitor varies depending on the material between the plates. The presence of water in the rock changes its physical properties, which should be perceived by the sensors. They are small, easy to install, robust, cost-effective and laboratory tests showed clear reactions to external influences.For the present work, prototypes of the sensors were drilled into the outer wall of the Leonhard Church in Graz. In addition, reference sensors were installed to determine the humidity via voltage and heat capacity values. In winter 2017/18, data from three measurement series were recorded, compared with values from the climate station "University of Graz" and evaluated. In particular, the reaction of the sensors to precipitation events and the subsequent drying of the masonry were to be investigated. No clear correlations were found. The sensors seem to react to various factors, such as the rock temperature. All other influences remained unknown. In addition, the sensors were installed in different building materials, which made the evaluation even more difficult without prior calibration. As a result, they could not deliver the hoped-for results in the current state of development.