Mould can release spores that can make you sick. Breathing in mould spores may cause health problems, especially for people with asthma.

If you can smell mould, you should look for it in dark, damp areas.

Removing mould

To clean mouldy areas you should wear rubber gloves, goggles and an N-95 mask (you can buy them at hardware stores).

When cleaning mould:

  • Remove mould by using a vinegar solution of 8 parts vinegar to 2 parts water (i.e. make a 500ml solution with 400ml vinegar with 100ml water). Leave for 20 minutes, and then lightly sponge with clean water.
  • Alternatively, you can use a 3% tea tree oil solution (i.e. two teaspoons tea tree oil in two cups of water in a spray bottle). Shake before use.
  • Do not dry brush the area as it can release spores into the air.
  • Do not use bleach.


Note: Consider professional cleaning on valuable or important items as the above cleaning methods may cause damage to some surfaces.

Preventing mould

To stop mould, you need to control moisture. This means drying wet surfaces, and reducing humidity and condensation in your house. Household humidity should be 30–50%, and you can buy a humidity meter at the hardware store to measure it. De-humidifiers can be used in rooms where there is a problem.

  • Ventilation: open windows to allow ventilation. Use bathroom fans when showering, and exhaust fans when cooking. Vent appliances that produce moisture, such as clothes dryers, to the outside if possible.
  • Heating: dry heating will reduce moisture. Continuous low level heating is better than short bursts of high heat. Open curtains to allow lots of sunlight into your home, and consider installing skylights in darker areas.
  • General household maintenance: ongoing maintenance to fix leaks and prevent moisture problems is important. Ensure weep holes are not blocked (weep holes help dry out internal wall cavities). Weep holes are also on aluminium window frames so water does not pool in the lower part. Ensure seals are intact on doors, windows and in wet areas. Cut back overhanging trees above the roof, and ensure garden beds slope away from the house to allow water to runoff.