An experimental study of mould growth and wood decay in timber frame walls

IRG/WP 17-20623

M Vanpachtenbeke, J Van den Bulcke, I De Windt, J Langmans, S Roels, J Van Acker

This paper deals with parameters related to the occurrence of mould growth and wood decay in timber frame walls. In a first part, the hygrothermal conditions inside a timber frame wall finished with brick veneer cladding are analysed to get an idea of possible moisture related problems. It is shown that, based on the VTT mould prediction model, there is a mould risk on the interface between the insulation material and the wind barrier. As up to now no fully adequate methodology has been developed to predict service life of wood, the purpose of the present project is to obtain a thorough understanding of the onset and progress of fungal growth on wood and wood-based panels and the impact on the in-service performance of these building materials. Therefore, in a second part, the reader is introduced to the fungal control unit (FCU), designed and elaborated at Woodlab-UGent. Some very preliminary results are presented. In a first test stage, samples of Norway spruce, Scots pine and OSB were exposed to a constant climate of 25°C and 97% RH. After a period of 90 days, severe mould growth was observed on the Scots pine samples, whereas mould growth on the OSB sample was less prominent. The Norway spruce samples were visually not affected by mould growth, except for the area around knots. Furthermore, based on the resonalyser technique, a loss of stiffness is observed for all samples. This is however probably rather caused by the changes in moisture content and dimensions than due to fungal decay.

Keywords: mould growth, wood decay, Fungal Control Unit, timber frame walls, hygrothermal conditions

Conference: 17-06-04/08 Ghent, Belgium

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