Predicting mould growth in buildings is essential to avoid environmental, financial and health damage. It is an important factor in evaluating indoor air quality through the quantification of spores emitted by the fungal colonies. Most of the spores that are found indoors are transported from outside either by ventilation or by the occupants and in favourable conditions these spores germinate, grow and emit spores indoors. The aim of this paper is to model the full cycle of air-born spores from their exchange between indoor and outdoor environments to their deposition on indoor surfaces, germination, growth, and multiplication. Two mould growth models, i.e., the VTT and the isopleth models, are implemented in 0D/1D components in the BuildSysPro QAI library to evaluate the mould contamination on surfaces. Three different air change rates (ACR) are considered to study their effect on mould formation (0.5 h-1 , 0.3 h-1 and 0.2 h-1). The mould index and the mycelium length are compared in these three scenarios. The results show that even at a very low air change rate (0.1 h-1), resuspension of spores from the floor does not have a significant impact on the concentration of spores in the air.