Words: Cleaning & Maintenance Management
Following recent flooding events in Queensland and northern New South Wales, air tightness – the practice of sealing one’s home to prevent indoor air from escaping and unwanted outdoor air from entering – has emerged as the most significant factor in predicting indoor mould spore concentrations in impacted residential buildings.
According to a study published in Environment International, an open access, peer-reviewed scientific journal, air tightness, in combination with other factors such as flood depth, ventilation systems and window blind status, plays a crucial role in determining the severity of mould growth in homes.
Alfred’s flood risk to northern NSW
As remnants of ex-tropical cyclone Alfred continue and heavy rainfall batters Queensland and northern NSW, the importance of air tightness in preventing the growth of mould is evident. The storm caused extensive flooding, with waters remaining stagnant for extended periods in many areas, creating ideal conditions for mould development. Homeowners are only just beginning to return home in some areas, with more than 200,000 homes across South East Queensland and northern NSW suffering power loss at some stage. While the floodwaters recede, materials such as carpets and drywall remain damp, providing a persistent source of moisture leading to the proliferation of mould.
The Environment International study found that maximum flood depth showed a consistent correlation with increased mould spore counts. This means that areas that experienced deeper flooding are more likely to face severe mould issues. However, air tightness was found to be the most significant factor in predicting the concentration of mould spores, regardless of flood depth. In regions affected by severe flooding, the air tightness of homes was the most reliable predictor of indoor mould levels.
Other factors influencing mould growth
While air tightness is a crucial factor, the study also highlighted the impact of other variables on mould spore concentrations, noting that factors like the presence of… also noted that factors like the presence of bathroom exhaust fans, central air ventilation and the condition of window blinds had an influence, although to a lesser extent.
Roof age was another factor found to have a small but notable impact. Older roofs may be more prone to leaks, which can contribute to moisture problems inside the home. Homes with poorly maintained roofs are more likely to experience prolonged dampness, providing the ideal environment for mould growth.
At the time of writing this article, Queensland has made steps towards recovery, with all emergency alerts now redacted as rainfall eases and rivers recede, the state’s premier says. Emergency alerts have also all been dropped.
As both states continue to recover from the impacts of ex-tropical cyclone Alfred, it is clear that addressing air tightness is a critical step in preventing long-term mould issues. Homes affected by flooding should prioritise sealing leaks, ensuring proper ventilation and addressing any other moisture-related issues to reduce the risk of mould. By taking these steps, homeowners can protect their living environments from the persistent and harmful effects of mould following major flooding events.
A version of this article was originally published on CMM
