In situ assessment of superficial moisture condition in façades of historic building using non-destructive techniques

Abstract

In historic building the water resistance capacity of their external materials is a relevant property that must be known, because the materials play a fundamental role in the interaction with the external environment. The aim of this research is to evaluate in situ the superficial moisture condition in facades using non-destructive techniques (NDT). Two different moisture measuring NDT was used: Infrared Thermography (IRT) and Electrical Resistance Measuring (ERM); in addition, the Air Temperature and Relative Humidity were measured. The IRT identifies the temperature of the material and offers a thermal image with different temperatures that is interpreted as moisture area. A Moisture Mapping is obtained with ERM, which represents the moisture conditions in the facades. Both techniques give an idea of moisture areas. The results of both graphics shows that the most humid areas correspond to the same areas that obtain by IRT and ERM. In conclusion, using these two NDT at the same time it is possible to acquire usually a quick, qualitative, precise and economic results of: moisture areas in situ, important data to survey and the assessment the historic building for monitoring or preservation project. Keywords: In situ assessment, Moisture condition, Infrared thermography, Moisture mapping, Electrical Resistance Measuring, Non-destructive technique