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Where does mould come from?

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Where does mould come from?

By Ruth MacEachern

Product Manager

Dec 13, 2022

The presence of mould in your home is not just unsightly, it can be dangerous to your health, and is often a sign that there is an underlying damp problem that could cause severe damage to the fabric of your property resulting in expensive redecorating and repairs.

Mould is a type of fungus which grows into large flat patches, and spreads through microscopic spores that are released into the air as the mould bodies mature. Mould spores can be carried over long distances and remain inert until they find an environment where they can grow. In a domestic setting, mould will often grow in damp areas with poor airflow that allows the spores time to settle and provide them with the nutrients they need.

Condensation, damp, and mould

In the home, mould is commonly found on ceilings and walls in bathrooms. When we bathe, water vapour is released into the air, and if the room is not well ventilated, the water vapour will condense on cool surfaces, and over time, can soak through to form damp patches.

Condensation is one of the most common causes of domestic damp, and this damp creates the perfect place for mould to grow.

Where do mould spores come from

The spores that give rise to colonies of mould can be carried long distances and carried into your home on breezes and even on clothes. If you were to look at domestic dust under a microscope, you would find many inert spores. Only a few spores need to settle in a suitable area for a colony to take hold.

If you already have mould in your home, it can spread quickly. It takes around a day for a spore to germinate, and the mould will begin to colonise an area in about three days. At first, the patch of mould will be hard to see, but after about 3 weeks, it will have spread to the point where you can see black patches appear on walls.

The health risks of mould

Mould can be damaging to your health. Some species such as Stachybotrys Chartarum – often known as toxic black mould – are particularly harmful. This type of mould releases chemicals known as mycotoxins which are very hazardous to health, and it needs to be removed professionally. Other moulds can also make life uncomfortable. In higher concentrations, mould spores are an irritant and can cause a severe allergic reaction if inhaled. People with respiratory conditions such as asthma and those with weaker immune systems can be affected by mould. Symptoms can vary from person to person, but include a cough, itchy skin, and painful eyes depending on what has come into contact with the mould.

Cleaning mould

Mould can be temporarily cleaned from surfaces using either a fungicide or diluted bleach, but it will quickly grow back if you do not remove the conditions that have allowed it to get a foothold.

Provided that you are not dealing with toxic black mould, you can wipe it off walls with a soft cloth. Wear eye protection, gloves, and a mask when cleaning mould to prevent contamination, and wash your clothes immediately after you have finished. You should throw away the cloth that you use to prevent spreading the mould to other areas.

Preventing mould

To stop mould growing back, you need to get rid of the damp patches that it develops in. In most cases, this means reducing the amount of moisture in the air. Mould develops in bathrooms and kitchens when condensation is allowed to form. Ensuring that you have good ventilation and use your extractor fans whenever you bathe, or cook will help to lower humidity levels and reduce condensation.

The most effective way to prevent mould throuhgout your home is with a whole house ventilation system such as Atmos - a Positive Input Ventilation system which draws fresh filtered air from outside into a central unit and then distributes it through all your rooms to displace the moist air that would otherwise lead to condensation.

Learn More about Getting Rid of Condensation >

Get help today

If you have discovered mould growing in your home, it is important to act quickly to minimise the risk to your health. Book a free home survey from one of our local ventilation specialists. They will visit your home, identify the cause of mould and condensation, and provide you with advice about the best way to deal with the problem permanently. Simply enter your postcode below to find your local expert.

Need help with condensation, mould or damp problems?

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During the free survey we will

  • check Assess any condensation, damp or mould problems in your property
  • check Take readings of the relative humidity levels
  • check Identify any underlying problems and make recommendations for a permanent solution

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