While there are contradictory views surrounding the severity of the effect that mould can have on your health, there is a unanimous agreement that there are health risks associated with its presence – irrespective of whether it’s from the actual mould itself, or the conditions required to allow it grow in the first place.

For mould to grow, it requires food (organic matter), warmth, oxygen and moisture. If there is mould growing within your home or building, this is indicative of a larger problem; mould is a symptom rather than the issue. The only element that mould needs to grow which we can realistically control is moisture. Mould will grow when there is an excess of it within the air and therefore moistens the surfaces within your building. We have explored the different ways that excess moisture can enter your building or home in previous blogs (see The Four Types of Damp and Relative Humidity) and the potential ways to control it.

According to the World Health Organisation (WHO), it is estimated that in Europe, 10-50% (depending on country) of indoor environments where people live, work and play, are damp.

Health Risks

As previously stated, there are contradictory views over the severity of illness that mould can cause. There have been some reports – from all over the world – of fatalities linked to mould, however, no causal link has ever been proven and these reports are rare.

Both the WHO and the NHS agree that exposure to mould can cause an increased risk of experiencing respiratory symptoms, infections, allergic rhinitis and asthma. Inhaling or touching mould spores can also cause allergic reactions such as sneezing, a runny nose, red eyes and skin rashes. Mould is also cited as a cause of asthma attacks.

Other common symptoms of mould have been reported as:

  • Coughing
  • Sneezing
  • Constant tiredness
  • Eye and throat irritation
  • Headaches
  • Skin irritation and rashes
  • Nausea
  • Chest tightness / difficulty breathing
  • Nosebleeds

A professor from the University of Manchester claims that tens of thousands of people in the UK are affected by mould. And while there are thousands of varieties of mould, only about ten of these actually cause any health concerns, and then they are namely sinusitis, bronchitis and other respiratory conditions and allergies.

Babies, children, the elderly, those with existing skin conditions (such as eczema) or respiratory problems (such as allergies or asthma) are all particularly vulnerable to mould, as are those who are immunocompromised (such chemotherapy patients).

The housing health and safety rating system (HHSRS), which local councils use to determine if there are health risks within rented accommodation, declared mould and damp as a ‘Category 1 Hazard’ in 2001 – the same category as exposed wiring, broken boilers, rats and vermin. If an assessment shows that there are Category 1 Hazards present, the council must take action.

Toxic Mould

‘Toxic mould’ has become a common term. However, according to the CDC (the Centre for Disease Control and Prevention), the term is inaccurate. While certain mould is toxigenic, meaning that it can produce toxins (specifically mycotoxins), the mould itself is not toxic. It is also important to remember that certain conditions have to be met for mycotoxins to form.

Mycotoxins are toxic chemicals that are produced by certain moulds. When produced, they can be present on mould spores and the small fragments of mould and fungus that are released into the air. They are lipid-soluble and are readily absorbed by the intestinal lining, the airways and skin.

The most common indoor mycotoxin-producing moulds include Alternaria, Aspergillus, Penicillium and Stachybotrys – often referred to as ‘toxic mould’ or ‘black mould’.

Exposure to certain mycotoxins (not necessarily those produced by the moulds listed above) can lead to adverse health conditions including cancer, and in some cases, can even be fatal. This is influenced by the type of mycotoxin exposed to, exposure levels and exposure time.

Although a scary thought, consider the fact that other mycotoxins have been used as ingredients in antibiotics, so it is imperative that you do not panic when you see mould, but instead, you ensure it is removed effectively and measures are taken to prevent its regrowth.

As noted above, it is imperative to remember that certain moulds produce certain mycotoxins which have their own symptoms, and strict conditions must be met in order for mycotoxins to form. Just because there is mould present that can produce mycotoxins, doesn’t mean that it will.

If you, or anyone you know, is experiencing symptoms which you believe are the result of mould or mycotoxins, consult your GP for more information and advice.

Structural Damage

Actively growing mould feeds on organic matter such as wood, paper, cardboard, fabrics and soap. As it feeds and grows, the mould gradually damages the surface, which can cause unsightly damage to the interior of a building.

Mould prefers more nutritious material than wood and therefore, surface mould on lumber is often mostly superficial. The mould itself doesn’t eat the wood or cause rotting, but rather it should be looked at as a symptom of something far more problematic; a high level of moisture.

If this high level of moisture is left untreated, it can cause the growth of wood-decaying fungus, which can result in catastrophic damage. Brown rot is the most destructive type of deterioration caused by decay fungi.

Mould itself isn’t a cause for concern regarding structural integrity, but more so what it represents. Mould cannot grow without moisture, so once it has started to appear, it is a good indication that there’s excessive moisture in the building.

If a building’s fabric is left to become excessively damp, it can not only lead to surface damage such as peeling paint and paper, but it can also blister plaster and increase the risk of decay in any masonry. It also increases the possibility of both dry and wet rot in timber – which in turn increases the chance of insect attacks, which only exacerbates the damage further.

Damp in the winter should especially not be ignored. If there is excessive moisture in porous building materials, there is a high chance that it can freeze during cold temperatures. As the moisture freezes, it expands and shatters the surfaces of surrounding bricks and tiles. If this recurs several times over an extended period, it can have a significant effect.

In extreme cases of damp, walls can become unstable. This has the potential to seriously jeopardise the structural integrity of the building and will require inspection from a Structural Engineer.

No Mould Should Ever Be Ignored

No mould should ever be ignored and it should always be treated as soon as possible, with the underlying cause identified and rectified accordingly. Whilst some mould is possible to clean yourself, other instances will need professional help (click here for further details) – we explore this further in our next blog.