Newcastle Borough Council - Dampness and Mould Growth

Housing

Owner Occupiers

Dampness and Mould Growth

There are many causes for dampness in the home. It can be caused by leaks, rising damp, rainwater and condensation.

Dampness is a major source of disrepair in a house and can be caused by several factors such as:

leaking pipes, wastes or overflows
rain seeping through the roof, spilling from a blocked gutter, seeping in around window
rising damp due to a defective damp course or missing damp course
condensation where moisture in the air condenses onto cold surfaces

Damp can cause mould growth, can cause wood to rot and other materials to decay. It will spoil decorations and will encourage development of mites and increase the risk of respiratory illness.

Avoiding condensation

Condensation normally occurs in the coldest months of the year and is due to moisture being held in the air. This moisture is naturally present; however, cooking, washing, bathing and drying clothes all produce excess moisture.

When this air meets a cold surface e.g. an external wall or window, it condenses i.e. it changes back into water causing damp patches and misty windows. As moulds and fungi prefer damp conditions, the damp areas provide an ideal environment for mould growth.

Unfortunately, there are no instant cures for condensation. However, if the guidelines below are followed, the level of condensation in your home can be reduced to a manageable level.

Produce less moisture

Use lids on pans
Do not leave kettles boiling
Simmer foods gently
Avoid the use of paraffin and portable flueless bottled gas heaters
Dry washing outdoors
Add cold water to the bath before the hot water
Vent tumble driers to the outside

Ventilate to remove moisture

Keep a small window or a trickle vent open when someone is in the room
Ventilate kitchens and bathrooms when in use by opening windows wider
Use a humidistat controlled electric fan, which come on automatically
Close kitchen and bathroom doors when they are in use
Ventilate cupboards and wardrobes and allow space between them and the wall
New window units should incorporate trickle ventilators

Insulate, draught proof and heat your home

Insulate your loft
Consider cavity wall insulation - see the Council's web page on Energy Efficiency Grants
Consider secondary and double glazing of windows
In cold weather keep low background heating on all day

Mould growth

To remove mould, wipe down walls and window frames with a quarter strength bleach solution or a fungicidal wash. Be careful to wear rubber gloves and not to spill the solution on clothes and furnishings. Dry clean mildewed clothes and shampoo carpets. Decorate using fungicidal paint.