A bio-hygrothermal mould growth analysis of typical Australian residential wall systems

Since 2014, Australian scholars and design and construction professionals have raised concerns about the increased presence of mould and condensation within new stand-alone and multi-residential buildings. Several studies have identified significant material decay and mould growth within external wall systems due to long-term moisture accumulation. This paper focusses on moisture and mould growth in buildings by providing an in-depth analysis of the most common external wall system for Australian residential buildings (cavity brick veneer). This wall's moisture accumulation over a ten-year period was simulated using multi-year transient hygrothermal software. Transient hygrothermal simulation is novel within the Australian research and regulatory context. Mould growth was simulated and analysed using a post-processing mould growth software. To assist in informing regulatory development, simulations were completed for three temperate Australian climate zones. The modelled wall system applied typical and regulation-compliant building material configurations for pre-2003, 2004, 2007 and 2010. The results of the modelled wall system will be used to inform national building regulations in Australia. A key component of this paper includes the evaluation of internationally accepted methods for mould growth simulation.