Surface mould contributes to the grey colour of unpainted wood exposed outdoors over time [1]. When planning building facades, mould growth models could thus be used to visualize the colour development and in that way facilitate a successful design. However, existing mould growth models for wood are mainly intended for indoor conditions [e.g. 2-4]. They are based on relative humidity (RH) and temperature as climatic input-data and do not consider effects of transient wetting by liquid water. This limitation might be solved by calculating microclimatic conditions [5]. The VTT mould model [2] is commonly used, but its performance under conditions that include liquid water is not known. In this study, we use data from a laboratory test that included transient wetting [6] to validate the original VTT model [2] for Scots pine sapwood and heartwood. Different estimates of RH are tested in the model and the results are compared.
Keywords: claddings, surface mould growth
Authors
Solrun Karlsen Lie
Norwegian University of Life Sciences, Norway
Thomas K. Thiis
Geir I. Vestøl
Olav Høibø
Lone Ross Gobakken
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