Mould Problems, Prevention and Cleanup Methods

One of the main consequences of moisture problems in a home is mould. Mould is part of a group of micro-organisms called fungi that also include mushrooms and yeasts. Mould is familiar to most people as food spoilers on items such as bread or fruit. Mould is nature’s decomposer in the food chain. However, if allowed to grow inside dwellings, mould can be a problem.

Mould can cause:

• unsightly stains;
• damage to paints, wood, drywall, ceiling tiles and fabrics;
• damage to personal items;
• allergies; and
• illness.

While mould itself does not cause damage to the structure of a house or building, it is a sign of potentially problematic moisture conditions that may eventually rot out wood framing and corrode structural steel.

Some symptoms:

• discolouration on surfaces such as walls, ceilings or furnishings;
• black marking or accumulation at the bottom of window frames and on windowsills;
• stains on carpets;
• mould on drapes and backs of furniture against exterior walls;
• stains on personal items close to affected areas such as storage boxes and clothing;
• musty smells; and
• rotting wood.

Mould Prevention

Mould requires moisture and a food source to grow. Some mould species can start growing if the RH of the indoor air is high enough while others require water.

To avoid most mould problems, keep materials dry by controlling moisture, providing ventilation and keeping indoor surfaces at high enough temperatures to prevent condensation.

If mould is present, clean the affected area as soon as possible, and identify and fix the source of moisture that allowed the mould to grow.

Mould Cleanup Methods

Small areas of mould can be cleaned using an unscented detergent and water. The mould area is considered small if there are fewer than three patches and each patch is smaller than one (1) square metre. If there is more than three patches or the areas are larger than one square metre, a trained mould remediation professional should assess the situation and recommend a solution. A trained contractor may be needed to clean extensive areas of mould.

When cleaning even small areas of mould:

• use household rubber gloves;
• use a mask, rated N95, capable of filtering fine particles;
• use protective glasses;
• after the clean up, rinse well with a clean, wet rag; and
• dry completely and quickly using fans and heaters.

Mouldy ceiling tiles and carpets are typically difficult to fully clean and should be removed and discarded. Drywall that remains stained after cleaning with detergent and water may need to be removed as well. Try washing fabrics but if the mould odour or stain persists, they should be discarded.

The proper cleaning procedure involves removing the mould. Chemicals such as bleach and fungicides are not recommended. It is important to remove all mould residues as they can cause allergies or illness.