Mould – Health Implications and Removal Strategies

February 19, 2015

By Roger Charnock – Chartered and Registered Building Surveyor

We generally think of problems occurring with buildings that leak during winter with extensive periods of rain. During the drier months leaking issues are usually forgotten about. This summer has been especially dry, with records stating it is the driest in over 40 years. It is during these dry spells that moulds release spores into the atmosphere in order to survive; much like fruit trees when under stress. This is essentially when moulds are at their most harmful as the spores can be allergenic or carry toxins.

Did you know that mould spores have been around longer than people?
Mould and fungi essentially live in forests and are necessary as part of the decay process of fallen leaves, branches and trees. Moulds have adapted to thrive off man-made cellulose products. Many of these products we use in modern buildings. For mould to survive it needs moisture and cellulose (wood based fibre) as a food source. Cellulose can be in the form of paper, wood or wood-fibre based products. Initially signs of mould growth may be minuscule, but given the right conditions these can proliferate.

Mould can be detrimental to your health when in high concentrations.
The type and amount of spores within a closed environment can have implications on building occupant’s health. The extent of how moulds can affect a person’s health is difficult to determine and is influenced by the individual’s immune system, age and health. Many spores we deal with are either allergenic or toxic and in high concentrations can cause flu like symptoms and respiratory problems until the source is removed. Spores are commonly found in outside fresh air, but it is when we have high concentrations of spores that there can be issues.

Mould is often found in damp buildings; dampness can be caused by external weather-related leaks, internal plumbing type leaks, damp subfloors or poor ventilation and or insulation. Certain moulds are toxic and need to be carefully removed. The toxins are chemicals that sit within the spore-shells, so ‘dead’ or non-visible spores still carry toxins. Bleaching merely hides the mould growth and spores. The mould and spores need to be physically and safely removed.

Stachybotrys is one such mould which we, as building remediation specialists, come across a lot. This is a black/brown mould and can have a fluffy appearance when dry. Strict handling and removal policies must be adopted when moulds are identified to ensure both building occupants and those removing and handling mould affected products remain safe and healthy.

The symptoms certain moulds are alleged to cause include:

• Mental and neurological affects
• Respiratory difficulties
• Circulatory complications
• Vision and eye problems
• Skin problems
• Immune system problems
• Reproductive system issues
• Tiredness and discomfort
• And other health effects

So what should you do when you find mould, particularly within wall or ceiling cavities?
The first stage is to get the mould tested; this can be done via air testing, swab testing or sample testing. As building surveyors we carry out sampling which is then tested by an external agency such as Biodet Services Ltd, who are microbiologists and can identify the types of mould present. Testing can provide indications on the length of time the mould has been active and the level of moisture present. Air testing in particular produces a spore count so tends to quantify the problem.

A qualified building surveyor is able to identify the location of dampness or water ingress; however a more detailed investigation may be needed to determine the cause. Once the cause is known the repair method and remediation strategy can be formulated to remove the mould in a safe and cost effective manner.

Many residential and commercial properties contain mould issues due to faults or defects that over time have created environments conducive to mould growth. The risks associated with these mould issues cannot be underestimated. A quick and easy solution may be all that is required, but to gain true peace of mind when you encounter mould or other signs of leakage it is best to get your property visually inspected by a building surveyor and have any mould samples examined by a microbiologist. Then, if necessary, get the property fully inspected so an effective repair solution can be established.

To find out more about how we can assist with mould issues visit our Leaky Building Resource page, alternatively contact us on 0800 PRENDOS, email

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