Fighting back against mould

Property and facility managers must learn how to combat the very real risks to people and buildings from mould outbreaks, Cameron Cooper writes.

Dripping humidity and an unexpectedly wet summer in parts of Australia have resulted in an all-too-common problem – mould outbreaks. In one extreme case, the Willyama High School at Broken Hill in New South Wales will have to be demolished and rebuilt because of mould that has infested carpets, chairs and plasterboard.

Scott McFadzen is a director of Coach8, a school offering Institute of Inspection, Cleaning and Restoration Certification (IICRC) training for the cleaning and restoration industry.

McFadzen says the recent floods in Queensland and New South Wales, plus cyclones in northern Australia, have highlighted the fact that many buildings are not being dried, cleaned or remediated correctly after flood and water damage. This puts buildings at risk of fungal growth and mould threats.

“The fact that there is so much false information and that it is so readily available, leads to poor and uneducated decisions being made,” McFadzen says.

“Unfortunately, facility managers don’t put being trained on water-damage management and correct mould remediation, from appropriate sources, high on their priority list.”

For McFadzen, the best solution is to prevent mould in the first place through the application of sound methods, techniques, standards and practices that are widely recognised in the engineering and construction industries. In practical terms, prudent construction may include:

  • thorough planning and assessment of potential risks before starting a building project
  • adherence to industry standards and regulations to ensure safety and compliance. The National Construction Code outlines requirements to prevent water and moisture from entering a structure
  • quality-control measures to maintain high standards throughout the construction process.

“Proper moisture management is crucial for building durability, occupant health and overall structural integrity,” McFadzen says.

He adds that heating ventilation and air conditioning (HVAC) systems can play an important role in controlling surface dew-point temperatures within buildings.

“Physically removing mould contamination is the primary means of remediation.”

Scott McFadzen


Any exposure to mould should be taken seriously. Mould spores can trigger allergic reactions and respiratory issues, while some species of mould can produce mycotoxins that pose severe health risks. They can also wreak havoc on buildings by infesting organic materials such as wood, plasterboard and insulation. According to World Health Organisation guidelines on indoor air quality, it is estimated that dampness and mould affect up to 50 percent of homes in Australia.

John Liddell is the founder of The Mould Doctor, a mould-remediation business that does thousands of mould inspections a month across Victoria and New South Wales.

“Identifying the cause of mould is not complex,” he says. “It’s usually building defects, high levels of humidity caused by condensation, or inadequate ventilation.”

Liddell says modern apartments that are built to achieve a six-star energy rating are often “tightly sealed”, meaning warm air cannot escape and cool air cannot enter the buildings.

“Most of them, unless they’ve got air-exchange systems installed, are like stepping into a sauna,” he says.

All mould, regardless of colour, is irritating to everyone, and allergenic for about one in five people. Any type of mould should be collected from the environment to prevent it from becoming airborne and resulting in inhalation exposure. Focusing only on certain types – that is, black mould – is not prudent or protective.

Liddell says another major problem is that property owners and tenants typically turn to bleach to kill mould.

“But there’s two things to remember – bleach doesn’t kill mould, it feeds the mould, and bleach is a very toxic product that can adversely affect people’s health,” Liddell says.

For mould control, The Mould Doctor offers a combination of thorough inspections to test humidity and moisture levels and identify the cause of any mould; micro-cleaning of a site and the physical removal of visible mould; and decontamination fogging to target airborne mould spores, bacteria and chemical volatile organic compounds (VOCs).

Liddell adds that when the humidity level surpasses 55 percent, it creates the perfect environment for mould to grow. Dehumidifiers offer an efficient and cost-effective method for managing moisture in areas up to 60 square metres.


Dr Brad Prezant, managing director of consultancy Prezant Environmental, is well versed in how high ambient humidity and poor indoor moisture management can cause mould problems.

As an occupational health scientist, he advocates better ventilation of buildings, installation of HVAC systems that control the indoor climate and exchange of air, and avoidance of “vulnerable” construction materials such as soft woods that absorb too much water.

He also notes that modern air-conditioning units in homes have complex inverter-based compressors and fans that, in their quest for better energy-efficiency, often re-evaporate a lot of moisture back into rooms.

“So, we’re not dehumidifying rooms as much as we used to,” Dr Prezant says. “We’re using less energy to accomplish comfort, but we’re not managing the moisture in the air as well as before.”

The upshot is that “supplemental dehumidification” is required, with one apparatus to manage cooling and the other to remove moisture.

For mould prevention, Prezant offers three key pieces of advice. First, facility managers should ensure that HVAC systems are monitored and managed properly to avoid moisture build-up.

Second, cleaners should ensure that surfaces are free of dust and dirt, which will help stymie mould growth.

Third, efforts should focus on particulate matter collection, including using HEPA vacuums to gather dust, pollen, mould, bacteria and other airborne particles.

“You’re not trying to kill anything,” Dr Prezant says. “Of course, that’s the cheaper option. Collecting particulate that’s diffusely spread throughout an environment is a labour-intensive process, but that’s what is necessary.”

McFadzen agrees the priority should be to remove mould, not kill it. He cites techniques taught in the IICRC’s Applied Microbial Remediation Technician certification classes that draw on the ANSI/IICRC S520 Standard for Professional Mould Remediation, which states: “Physically removing mould contamination is the primary means of remediation. Mould contamination should be physically removed from the structure, systems and contents to return them to Condition 1. Attempts to kill, encapsulate or inhibit mould instead of proper source removal generally are not adequate.”


As facility managers weigh up mould risks, McFadzen says training on how to handle uncontrolled moisture ingress should be on the radar for them and their teams.

“Water damage, uncontrolled humidity, temperature differences, ventilation issues, building failures and building occupant behaviour are all factors influencing mould growth in today’s buildings,” he says.

“As these buildings change with newer material trends and our environment shifts with current climate changes, the need for facility management to attend to and understand water damage and the influences of indoor humidity will be required.”

Dr Prezant says mould prevention and efforts to improve air quality will continue to evolve. To date, for example, ventilation has been a go-to means of bringing clean outdoor air into buildings.

However, with air pollution worsening in some countries and exposure to fine particulate matter (PM2.5) being linked to allergies, lung cancer and cardiopulmonary diseases, all solutions must be on the table.

“We might reach a point where state-of-the-art when delivering the best air quality is not so much to bring in 100% outdoor air, but to actually keep the interior air and clean it,” Dr Prezant says.

“So, scrub it for chemicals, clean it for particulate, that sort of thing. It’s possible that we could move in that direction over the long term, but that’s really futuristic stuff right now.”

This article first appeared in the May/June 2024 issue of INCLEAN magazine.

Photo by Avinash Kumar on Unsplash

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