Mould: Causes and Solutions

18 January 2017
Get your property ready for the cold winter months
10 February 2017

Mould is one type of fungus whose job it is to decompose of dead organic material. Moulds sometimes can infect living plants and animals. The spores and fiber like structure of individual mould colonies are too small to see without a microscope.

What is Mould?

When enough mould grows together on a surface it will appear in different colours. The colour of mould is influenced by nutrient source and the age of the colony. It is impossible to determine what type of mould is growing by visual inspection only.

Moulds are naturally occurring organisms playing a major role in the earth’s ecosystem. They are the most important part of nature’s ability to recycle. These microscopic fungi exist everywhere except under water, parts of the Arctic and Antarctic, and in artificial environments like clean rooms.

Fungi have to depend on other organisms or on the forces of nature to carry them to a food source, or to bring food to them. Mould spores and mould fragments are in the air we breathe every day.


Mould: Causes and Solutions

It’s that time of the year again when the days are getting shorter and colder and that means that your house is more susceptible to mould growth. Mould growth is caused by either building defects, which wets building elements, or by condensation. Mould growth will develop on walls, furnishing, and clothes once dampness is present for a period of time. Mould fungus needs three conditions to grow (infection, nourishment and a damp environment) and these will be present in a dwelling once a damp environment is established for a period of time. It is considered by some that the presence of mould within buildings can contribute to serious health risks. Toxic moulds can cause a range of symptoms including headaches and a wide range of skin lesions and rashes. The areas where mould is located need to be treated using a suitable fungicidal wash. But this is a temporary cosmetic solution and the cause of the appearance of the mould, the damp environment, needs to be dealt with prior to redecorating.

What is the cause of black Mould on walls?

It usually grows in damp, warm conditions without much airflow, which is why household bathrooms and loft spaces often suffer from mould. It is often simply caused by humid conditions and lack of ventilation, but sometimes mould on walls can be due to plumbing leaks, both inside and outside the property.
Condensation occurs when warm moist air meets a cold surface. Its more likely to occur in winter because the building surfaces are cold and because windows are opened less, thus trapping the moist air.

Condensation is caused by a combination of:

  • Poor ventilation.
  • Unheated and poorly insulated rooms.
  • Excessive moisture in the air, i.e. from gas heaters, drying clothes indoors etc
  • Excessive moisture on the building element itself because of defects in the building and/or flashings.

How do you prevent condensation?

  • Turn Down the Humidifier. You might notice condensation in your bathroom, kitchen, or nursery.
  • Buy a Moisture Eliminator. …
  • Bathroom and Kitchen Fans. …
  • Circulate the Air. …
  • Open Your Windows. …
  • Raise the Temperature. …
  • Add Weather Stripping. …
  • Use Storm Windows.

Is Mould a health hazard?

Moulds produce allergens (substances that can cause an allergic reaction), irritants and, sometimes, toxic substances. Inhaling or touching mould spores may cause an allergic reaction, such as sneezing, a runny nose, red eyes and skin rash. Moulds can also cause asthma attacks.


  1. Maintain reasonable background heat levels in the property. If a room is allowed to cool the door into it should remain closed to prevent warm damp air entering from the remainder of the dwelling, and condensing in the room.
  2. Limit the drying of clothes internally and if clothes are dried inside they should be dried in well-ventilated rooms (with windows open) and with the doors closed to other parts of the dwelling.
  3. Limit the use of movable gas heaters, as this type of appliance releases large amounts of water vapour into the air, if they are used an external window should be left ajar in the room to allow fresh air to enter and the moisture produced to escape quickly.
  4. After using the bath the windows should be kept open/ or extract fan on and the door closed until all the moist  air is removed.

    Mould remedial action, based on building defects

  1. Remove mould from all surfaces where present by washing the surface with a suitable fungicidal solution and allow it to drying. A dehumidifier can be used to aid the drying. Do not attempt to brush the mould off the walls, as this will just spread it.
  2. Increase ventilation to rooms.
  3. Engage a specialist to inspect roofs, walls, balconies etc for leaks in water proofing membrane and flashings. Perhaps a DPC (damp proof course) or DPM (damp proof membrane) is missing or damaged. Bear in mind that water entering a leak can penetrate in one place, track along a surface and exit in a remote spot.
  4. Provide additional insulation to avoid cold spots on walls, floors and ceilings.
  5. Provide a mechanical extract fan to ‘wet’ rooms i.e. bathroom.
  6. Finally, the building should be regularly maintained by:
    • Checking, maintaining and clearing gutters, drains, gullies and downpipes.
    • Removing weed and plant growth from the building facades.
    • Carrying out regular inspections and repairing any damage to downpipes, roofs and gutters promptly.

How do you stop Mould on walls?

Scrub the surface mold stains from walls and wood trim with a mixture of 1 qt. water and 1/2 cup bleach to kill the mold. Use a soft brush and work until signs of the mold disappear. Wipe off, but DO NOT RINSE these surfaces. Set trim in direct sunlight to dry.

Symptoms of mold exposure can include:

  • Nasal and sinus congestion, runny nose.
  • Respiratory problems, such as wheezing and difficulty breathing, chest tightness.
  • Cough.
  • Throat irritation.
  • Sneezing / Sneezing fits.


For more information on how to remove mould, click on this page

Feel free to contact us at PINNACLE GROUP for all your property maintenance, repairs and cleaning jobs, we are available 24 hours and 7 days of the week.

T: 061 609 865 / 087 962 2222 / 086 311 4590


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