Damp & condensation

Keeping your home free from damp and mould

Damp can cause mould on walls and furniture and make timber window frames rot. Damp housing encourages the growth of mould and mites and can increase the risk of respiratory illness. Some damp is caused by condensation. The information below explains how condensation forms and how you can keep it to a minimum, so reducing the risk of dampness and mould growth.

What is condensation?

There’s always some moisture in the air, even if you can’t see it. If the air gets colder, it can’t hold all the moisture and tiny drops of water appear. This is condensation. Condensation occurs mainly during cold weather, whether it’s raining or dry. It appears on cold surfaces and in places where there’s little movement of air such as in corners, on or near windows, in or behind wardrobes and cupboards. It often forms on north-facing walls.

Is it condensation?

Condensation isn’t the only cause of damp. It can also come from: leaking pipes, wastes or overflows
rain seeping through the roof where a tile or slate is missing, spilling from a blocked gutter, penetrating round window frames, or leaking through a cracked pipe rising damp due to defective damp-course or because there’s no damp-course. These causes of damp often leave a 'tidemark'. Damp caused by condensation doesn’t leave a tidemark.

How to avoid condensation

There are three things you can do to avoid condensation:

    * Produce less moisture
    * Ventilate to remove moisture
    * Heat your home - always have a low level of   
       background heating, even when there’s no one at   
       home

Some words of warning!

Don’t block permanent ventilators.
Don’t completely block chimneys. Instead, leave a hole about two bricks in size and fit a louvered grille over it.
Don’t draught proof rooms where there’s condensation or mould.
Don’t draught proof a room where there’s a cooker or a fuel burning heater, for example, a gas fire.
Don’t draught proof windows in the bathroom and kitchen.

First steps against mould

First treat any mould you may already have in your home. If you deal with the basic problem of condensation, moulds should not reappear.

To kill and remove mould, wipe down walls and window frames with a fungicidal wash that carries a Health and Safety Executive 'approval number'. Follow the manufacturer's instructions precisely. Dry-clean mildewed clothes and shampoo carpets. Disturbing mould by brushing or vacuum cleaning can increase the risk of respiratory problems.

After treatment, redecorate using a good quality fungicidal paint to help prevent mould recurring. Note that this paint is not effective if overlaid with ordinary paints or wallpaper.

The only lasting way of avoiding severe mould is to eliminate dampness.