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Mould 2126-3.jpg

Mould can be a problem in several areas of a house. Each area has its own specific recommendations, but they all have some things in common.

Mould Basics

Mould needs 2 things to grow:

  • water
  • nutrients

These are only required in tiny amounts, slight condensation and surface dirt are plenty for mould to grow in.

Any of the following can prevent or kill mould:

  • Remove water source
  • Remove nutrients
  • Ventilate
  • Mould killing chemicals
  • Physical removal

The most effective mould prevention strategy is usually to reduce dampness.


Silicone Sealant

Silicone Sealant contains mould food, so mould loves silicone. Using a better quality type of sealant can much improve the situation.

Mould resistant silicones don't prevent recurrence, but can help delay recolonisation.

Removing and renewing sealants can greatly improve the situation for a while.

Regular cleaning can remove surface dirt. To remove mould & dirt even from badly mouldy silicone, apply folded loo roll and wet it with bleach. Leave overnight. Repeat this 3 or 4 times and black silicone can look like new.

Wiping water off after use can speed up drying.

Brushing acid on can remove scale build up which traps dirt.

Ensure cleaning chemicals are rinsed off properly so mould has nothing to feed on.

Shower Curtains

Mould traps dirt and moisture, leading to more mould growth, so nipping it in the bud is the way to control it.

  • Frequent washing will reduce surface dirt
  • Wiping with acid will remove scale, which traps dirt, which provides food for mould
  • Ensuring curtains are fully unfolded after use (and not pressed against flat surfaces) helps them dry out

Window Curtains

Cotton curtains can be washed at 60° to remove dirt & algae. Synthetic materials that don't wash at 60° can be harder to clean.

Cloth curtains are also porous, enabling drying out after use. Use of plastic shower curtain material for window curtains reduces their ability to dry and to be cleaned.

Windows & Walls

Mouldering window frames or walls indicates a damp problem, which should be resolved before wooden windows are badly damaged. Damp & mould can be reduced by:

  • Use of window after baths or showers
  • Ventilation fan
  • Dehumidifiers
  • Use of a closed shower cubicle, which reduces steam escape.
  • Regular cleaning to remove surface nutrients
  • Use of mould resistant paint can help to some degree
  • Leaving bathroom door open after bath or shower use

Other Rooms

The Bathroom section applies in part also to Kitchens.

Mould in other rooms means a damp problem. The cause should be found and fixed.


Large areas of black mould can have serious health consequences, and should never be ignored.

Precautions may be needed when mould is being removed.


Mould killing chemicals include:

  • Bleach
  • Copper compounds, use lightly to avoid green staining
  • Zinc sulphate
  • Borax
  • Various branded mould killers

See Also