This paper is part of a PhD field study that focuses on the importance of conducting a visual inspection and evaluation of the indoor climates in libraries. Libraries contain a large amount of stored books that require a stable relative humidity to guarantee its preservation. Mould can survive and grow when indoor relative humidity is high and fungus is present all the time in the air that we breathe. Recording data through visual inspection and field studies. Its recorded the indoor relative humidity, temperature and lighting to assess mould growth problems. The assessment technique for this paper is based on guidelines survey and literature review. Visual inspection found few symptoms of mould growth that related to the amount of moisture appeared when the relative humidity in the library increases. Finally, the recording data for temperature and relative humidity demonstrate the result show that the stable indoor climate in the library building. © (2014) Trans Tech Publications, Switzerland.