Mould - Building Biology
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You can’t always see or even smell it, however it affects almost 1 in 3 homes and can have devastating consequences on the lives of those who can’t make antibodies against it. I’m talking about MOULD which many are referring to as the next asbestos. So given that fungi are nature’s greatest decomposers and have been around well before us, why is mould such a problem now? Energy efficient homes are like plastic bags (air and water tight) with compromised passive ventilation. Consequently there has been a considerable increase in the number of complaints to the Building Commission about condensation issues. In addition we have gone from using natural building materials like hard wood timbers that naturally contain resins that are resistent to fungal attack to predigested particle board that has become the perfect fast food for mould. The two factors come together to create a toxic time bomb.

  • Preventing Mould after Floods and Extreme Weather. (July 2022). Youtube.  HERE
  • Audio interview: Mind Body and Mouth. Podcast. (July 2023) Mould
  • Hidden Dangers in your Home. Ron Malhotra. Podcast. (June 2023) HERE.
  • Health hazards in Australian Homes. Youtube. (April 2022). HERE
  • Read Body+Soul article ‘Mould – is it making you sick?’  Download PDF

The cause of mould is moisture

Micro-organisms require food and moisture to thrive. As microbes are everywhere on this planet, and most building materials and furnishings are the perfect fast food for mould, the key to addressing mould problems is to identify the source of the moisture. Once moisture sits on a surface for more than 48 hours, the microbes on the surface will attempt to take over the space by producing endotoxins, mycotoxins and microbial volatile organic compounds which can dramatically impact the indoor air quality and affect the health of the occupants.

  • condensation issues
  • plumbing, gutter or roof issues allowing moisture to penetrate inside the building
  • building on a flood plain or above a water course
  • poor drainage around the home
  • building into a hill, on or at the bottom of a hill
  • garden beds butting up against the house
  • living in humid areas (consistently above 70% relative humidity)
  • absent or insufficient water proof barriers in the wet areas of the home
  • insufficient subfloor ventilation
  • damage to the damp proof course
  • metal framed homes creates thermal bridges (condensation occurs)
  • concrete slab has not yet cured and is consequently releasing tonnes of moisture into the indoor air
  • water damaged timber used to build a home (or was left out in the rain during construction)
  • much more!

24% of the population cannot create antibodies to mould; so every time they go into a water-damaged building, it results in inflammation in their brain and their body which can be misdiagnosed as Chronic Fatigue Syndrome or even worse, a mental illness

Health effects

The chemical stew of microbes (bacteria and fungi) as well as their by-products (fragments, spores, endotoxins, mycotoxins…) is thought to be responsible for the health effects associated with a water-damaged building. Around a quarter of the population have a genotype (haplotype) that does not enable them to produce antibodies to fungi; so everytime they walk into a mouldy building, it sets up an inflammatory response in their body that doesn’t switch off. In contrast the rest of the population produce antibodies which enables them to recognise and clear these antigens from the body. This inflammation affects key neuropeptides in the brain – vasoactive intestinal polypeptide, melanocyte stimulating hormone and in some cases antidiuretic hormone which can cause many of the symptoms associated with Chronic Fatigue Syndrome (see below). This is why some people in a water-damaged home can get very sick, whilst their partners can be completely well.

  • Fatigue that is not alleviated by sleep which completely affects their circadian rhythm (microsleeps during the day, unable to sleep at night…)
  • Lung problems such as recurrent colds and flu that are difficult to get rid of, cough, sinusitus, hayfever, pneumonia.
  • Chronic fatigue syndrome: headache, sleep disturbances, brain fog (loss of words, poor short term memory, forgetful), fibromyalgia (unusual body aches and pains) and inability to thermoregulate (hot and cold)
  • About 30% of  patients will experience excessive urination and thirst (not related to diabetes) and easy to get shocked when touching appliances. This is due to changes in osmolality due to issues with Antidiuretic hormone.
  • Many patients go on to develop chemical sensitivity and electromagnetic hypersensitivity
  • Symptoms often improve when they are away from the building

Treating mould illness

There are very few health practitioners who have a good understanding of the devastating impact microbes in a water-damaged building can have on human health. I have dedicated 20 pages of information to Mould in the third edition of my book Healthy Home Healthy Family including what tests should be considered by your health practitioner to diagnose a mould-related illness. Here is a list of health practitioners who specialise in environmental illnesses here.

Testing the home for mould

In some of the worst homes affected by mould, I could not see any visible mould or smell dampness. Mould testing is a complicated procedure that may involve moisture mapping using moisture meters to determine the extent of the water-damaged materials; air, dust and/or surface sampling (which are then sent to the lab to be cultured and analysed) and the use of borescopes and thermal imaging cameras to identify hidden mould and moisture. If the area of visible mould exceeds one square metre, or if you are experiencing the above symptoms and your health practitioner is unable to identify the cause of your complaint, consider hiring a building biologist or IICRC accredited mould remediator to investigate.

Cleaning mould

There is a lot of hype on social media about how to kill mould that is completely unfounded, so I want to set the record straight in relation to the use of bleach, ozone and essential oils and their impact on mould. Bleach is ineffective in killing fungi (however, it is effective against bacteria), because it is highly alkaline and may provide the microbes in a water-damaged building with a food source. Furthermore, it only ‘bleaches’ the mould until such time that the melanin compounds in the hyphae (the branching filamentous cells of the fungus) recover and, voila, within weeks the mould becomes visible again. Similarly, ozone should NEVER be used in a water-damaged building because it is an eye, nose and lung irritant; it is ineffective at killing mould spores; it reacts with numerous volatile organic compounds in a water-damaged building to create more toxic chemicals; it may degrade the colours of surfaces such as paintings; and lastly, it is very reactive with synthetic materials such as plastics, nylon and the rubber backing on carpets and curtains. For these reasons, the US Environmental Protection Agency has issued warnings against using ozone inside a building. Whilst several studies have confirmed that tea tree and clove essential oils are remarkably effective antifungal agents, they should be used sparingly (or not at all) in mould remediation jobs because the amount required can be toxic to children and to chemically sensitive individuals. Furthermore, killing mould is irrelevant when most spores are already ‘dead’ (can’t germinate) but may still cause harm when they are inhaled.

The best way to deal with mould is to physically remove it. This can be achieved by conducting a HEPA sandwich which involves vacuuming the affected non-porous surface using a vacuum cleaner fitted with a HEPA filter, then wiping with a damp microfibre cloth, and vacuuming again. The microfibre cloth should be soaked in ½ litre of water to which a generous squirt of dishwashing liquid has been added. This procedure will remove the biofilm that microbes in a water-damaged building feed on. The cloths should then be rinsed thoroughly before reusing. At the end of the job, the cloths should be discarded along with the HEPA filter and disposable vacuum cleaner bag. For a detailed discussion on how to remove visible mould from porous (soft furnishings, unsealed timber, rugs…) and non-porous surfaces (hard timber, glass, metal, plastic, concrete…), or a checklist on what your mould remediator should do when remediating your home, buy my book Healthy Home Healthy Family.

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