The federal government has released findings from its inquiry into mould-related illnesses and moisture in buildings.
The parliamentary inquiry met in August and September to hear evidence from experts in health, biology and building physics. The committee received information about Chronic Inflammatory Response Syndrome (CIRS) and the wide range of associated symptoms that are often debilitating and difficult to diagnose and treat effectively. These include chronic fatigue, “brain fog”, unexplained weight gain, numbness and tingling.
It also examined the links between CIRS and mould in buildings, and the need to improve building standards around moisture control.
Witnesses at the hearings stressed the need for mandatory standards related to the prevention and remediation of dampness and mould in buildings. Currently, the Australian Building Codes Board (ABCB) has a non-mandatory guide for condensation in buildings, but it is not part of the National Construction Code (NCC).
Architectural scientist Dr Tim Law says that Australia’s codes “are decades behind international best practices in managing and responding to condensation problems”. He points to Canada and Ireland as leaders in this area, and says the UK, the US and New Zealand are also way ahead of Australia.
Jesse Clarke, M.AIRAH, is a building scientist at Pro Clima Australia and president of AIRAH’s Building Physics Special Technical Group (STG), which is supporting the coming Building Physics Forum. Over the past three years, the STG has been working to establish better standards for integrating building envelope design with HVAC systems.
“Prevention is better than cure – or a band aid,” he says. “This comes back to good design of the building envelope, and includes looking at the moisture storage and vapour-diffusion properties of materials in combination with the chosen HVAC systems for ventilation, heating and cooling set-points and indoor humidity levels.”
Building practices that were put forward to the inquiry as potentially increasing dampness and/or mould levels include:
- Exposing building materials to moisture during construction
- Inadequate ventilation (such as buildings that are air conditioned at all times)
- Practices that enable a build-up of condensation (such as the use of foil to wrap buildings)
- The use of timber framing and/or gypsum board that may encourage mould growth
- Inadequate and/or incorrectly installed waterproofing.
The inquiry also found that occupant behaviour – such as keeping windows shut at all times or flooding of sinks and baths – was a factor. Some of this may be related to changing work patterns that mean no one is at home to open windows. Clarke says this comes back to design.
“The building code requires the openable portion of windows to equal or exceed 5 per cent of the floor area, and assumes that people are cluey enough to open them and are home to do so,” he says. “Occupants may not open the windows for a variety of reasons including security, noise or keeping the rain out. This is why the internationally accepted solution is to have a continuous ventilation system, as regulated in the EU and US. Australia needs to catch up.”
Witnesses noted that the creation of highly energy-efficient and fireproof homes over recent years may have had the unintended consequence of increasing the incidence of condensation, and consequently increasing the risk of dampness and mould build-up.
“This is the truth,” says Clarke. “We are sealing using vapour-impermeable materials to prevent burning embers from entering roof spaces, with zero attention to the general rule of hygrothermics and good building envelope design. An assembly should be only as vapour tight as necessary, but as vapour permeable as possible. This means aluminium foil membranes do not have a place in the majority of buildings to ensure healthy outcomes.
“And we can’t upgrade the energy efficiency of the building envelope until we understand moisture-related issues and the interdependencies between thermal transfer and moisture accumulation.”