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Damp, mould and condensation

Some damp is caused by condensation. This can lead to mould growth.

Is your home showing signs of dampness and mould? There are some types of damp that are more serious than others. Here’s how to spot the difference between condensation and damp.

The cause of damp in a house is excessive amounts of moisture on internal walls and surfaces that cannot escape. There are three types of damp; condensation, penetrating, and rising damp.


What is condensation?

Condensation is caused when warm moist air comes into direct contact with a cold surface such as a wall, window or windowsill. When it comes to condensation, it is more prevalent during the winter months, unlike rising damp and penetrating damp. Rising damp and penetrating damp are more likely to cause problems during wet weather unless they are caused by plumbing problems.

When condensation is allowed to escalate, black mould patches appear on walls. Generally, condensation will occur in areas of the property where the air is still, like the corner of a room or behind furniture. Condensation can cause damp.

What can condensation do to your home?

As a result of condensation, mould can grow on walls, furniture, and soft furnishings (for instance, curtains). It can even rot wooden window frames and damage plasterwork. Damp conditions can also increase the number of house mites.

Mould and house mites can worsen breathing conditions like asthma and bronchitis, so you should control condensation in your home.

How to prevent condensation and control excess moisture
  • keep your home warm, especially when the weather is cold or wet
  • keep your home well ventilated
  • close kitchen and bathroom doors to prevent steam from going into other colder rooms
  • open kitchen and bathroom windows when cooking or washing so steam escapes, or use an extractor fan if fitted - leave these on for a while after you have finished cooking or washing
  • open some windows in other rooms for a while each day and open any trickle vents fitted in your window frames - this allows a change of air
  • wipe down surfaces where moisture settles to prevent mould from forming
  • do not block air vents and allow air to circulate around furniture and in cupboards
  • do not use bottled gas heaters – the gas produces a lot of moisture
  • measure humidity with a hygrometer, if the hygrometer is showing very humid, condensation and mould are likely to form, meaning you need to ventilate

Penetrating damp

What is penetrating damp?

Damp patches on your walls are a symptom of penetrating damp. These patches will appear larger after heavy periods of rainfall. The damp patches can be noticeable on both the inside and outside walls of the building.

Cracks or leaks in the gutters could lead to a penetrating damp issue occurring.

What can penetrating damp do to your home?

Penetrating damp can lead to black mould appearing on the inner walls of the property.

How to prevent penetrating damp

Penetrating damp refers to water that penetrates into a property from the outside. Generally, penetrating damp is caused by leaking gutters, broken pipes, or poor brickwork. Gaps in doors or windows can also cause problems.

Report penetrating damp issues as a repair on the housing services portal.

Rising damp

What is rising damp?

Rising damp occurs when groundwater rises through pores in masonry and saturates it. Generally, this type of dampness occurs in older properties without a damp proof course or where it has been damaged.

Although bricks might appear solid, closer inspection reveals that they are filled with voids. By using a chemical damp proof course, moisture can be prevented from rising.

Having tide marks on walls is one of the most common ways of identifying rising damp. These tide marks will not appear higher than one metre from the ground. There may also be damp patches or stains on the walls that appear yellow or brown.

Just like condensation, the wallpaper will start to peel off the walls, but the difference is that it will occur only on the lower parts of the wall. Rising damp can cause timber to decay if it comes into contact with it.

Unlike condensation, white salts will be present on walls.

How to address rising damp

Report rising damp issues as a repair on the housing services portal.

If mould forms

  • wipe the mould off immediately with water
  • do not use washing up liquid or bleach, apply a recommended product available from a hardware or DIY store
  • always follow the instructions carefully

Severe mould

We have a dedicated team that asses the problems of severe mould in your home. Fill in the mould reporting form and we will arrange an inspection.

Damp, mould and leaks policy

Read the damp and mould policy which sets out our approach to investigating reports of leaks, damp, mould; diagnosing the cause and implementing a solution.

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