Indoor microclimate diagnosis allows to understand the indoor-outdoor building microclimate interactions and to evaluate the extent of indoor hygrothermal variability caused by building use. Moreover, since the cumulative physical deterioration of the building envelope plays a relevant role in altering the indoor microclimate and building thermal performance, it is essential to combine both building envelope and indoor microclimate monitoring in an integrated diagnostic approach. The microclimate diagnosis of the Vleeshuis museum main exhibition hall here discussed is based on infield instrumental environmental monitoring and Infrared thermography (IRT) on the building masonries. The IRT was integrated with the analysis of the building documentation. Further, the microclimate analysis was performed by combining the conventional microclimate data analysis with statistical tests. The integrated diagnosis as presented in this study allowed to evaluate the long-term indoor micro climate variability consequent on outdoor and indoor heat and moisture loads variation as well as the identification of the sources of infiltrative water in the building masonries. (C) 2017 Elsevier B.V. All rights reserved.