Drying evaluation using infrared thermography

The effect of moisture in buildings is normally related with damage, which may occur due to the presence of moisture itself or due to its evaporation. The drying process plays an important role in the available moisture, both inside the material or at its surface, so its evaluation is of great importance. Infrared thermography (IRT) is a non-contact and non-destructive testing technology that can be applied to determine the surface temperature of an object. It is commonly used as a diagnostic tool, enabling studies related to the thermal behaviour of building elements as well as to identify anomalies and degraded areas. Although less common, IRT is also used to assess moisture in building components. In this work it was analyzed the applicability of IRT to assess the drying process of exterior walls after a long-term rainy weather. The test campaign started when the rain period stopped and a period of sunny days began. To assess the drying process, besides infrared camera, it was also used a moisture detector to evaluate qualitatively the walls' moisture content. Measurements were carried out during six consecutive days without rain, at 10:00, 12:00, 14:00, 16:00 and 18:00. Two walls were assessed:one facing southeast, exposed to direct solar radiation, and one facing northeast, with no incident solar radiation. Moisture detector results show that the walls dry out along the test campaign, being the drying process more intense in the wall facing southeast. That is mainly related to the fact that the wall was exposed to direct solar radiation during a longer period, which enabled the drying process to be fastened. The results obtained with both methods were combined and the opportunities and limitations of IRT to assess the drying process in outdoor conditions were discussed. (C) 2015 The Authors. Published by Elsevier Ltd.