Damp or condensation? What’s the difference and what to do about it

Are you concerned about damp and mould in your home? Some types of damp are more serious than others. Learn how to identify what type of damp you have and how to treat it with our easy-to-understand guide.

Are you concerned about damp and mould in your home? Some types of damp are more serious than others. Learn how to identify what type of damp you have and how to treat it with our easy-to-understand guide.

Chris King
Home insurance expert
8
minute read
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Posted 21 OCTOBER 2021

Identifying different types of damp 

People sometimes talk about damp and condensation as if they’re different things but, in fact, condensation is a type of damp. When dealing with damp and mould, it’s important to be able to tell the difference between damp caused by condensation, and other types of damp caused by issues such as groundwater, leaks and plumbing problems. 

While some types of damp can be wiped away, others could cause lasting damage to your home. Damp can also lead to mould and dust mite populations, which can increase respiratory problems and allergies. 

Read our guide to spotting these different types of damp and find out how best to treat them: 

  • condensation
  • rising damp
  • penetrating damp

Condensation 

Condensation is the most common type of damp. It’s caused by a combination of excess moisture in the air and poor ventilation. It could start from something simple, such as steam from the kettle, running the hot water or cooking pasta on the hob. If treated properly, condensation can be remedied without it causing lasting damage.

 

Spotting condensation 

The first sign of condensation is usually moisture drops on walls, mirrors or windows. These form when hot, moist air comes into contact with cold surfaces.

While these small droplets of water may not be troublesome right away, the effects of condensation can worsen over time, producing black mould and the beginnings of a damp smell.

Treating condensation 

If caught early, condensation mould can be easily treated at home using a cloth dipped in soapy water or with an antifungal spray that will kill the fungus. Remember to dry the area after you’ve cleared the mould. You could also treat the area afterwards with a mould-resistant paint to help prevent the issue reoccurring. 

Here are some easy steps you can take to prevent condensation in your home: 

  • invest in better ventilation systems, such as extractor fans or dehumidifiers in particularly damp rooms like your bathroom and kitchen
  • close the door and open the window when you’re using the kitchen or bathroom
  • use pan lids when you’re cooking
  • dry your clothes outdoors
  • place furniture a couple of inches away from external walls
  • leave your windows open to let your house air when the weather’s nice
  • air your wardrobes and cupboards occasionally and keep clutter to a minimum
  • make sure your tumble dryer vent is outside

Does home insurance cover condensation?

Most home insurance policies don’t cover damp caused by condensation. However, condensation can be managed and prevented at home – if you do this, it shouldn’t cause lasting damage.

Rising damp 

Rising damp can look a lot like condensation, but it has a very different cause. 

As the name suggests, rising damp starts at ground level and rises upwards, climbing your walls from the floor. It can cause more damage than condensation, so it’s important to be able to tell the difference between the two. 

Rising damp is more commonly a problem in older properties, where the damp proof course (DPC) - the barrier installed in the building’s structure to keep moisture out - is either damaged or missing. Without this barrier, water is drawn up from damp ground into the cavities between bricks and cement like a sponge, by a process called capillary action.

Spotting rising damp 

Much like condensation, rising damp produces dark mould patches on your walls, but there are a few distinguishing features you can look out for too.

Peeling paint or wallpaper, along with damage to skirting boards and loose flooring, could all point to rising damp. You may also notice tide-like marks and a white powder that looks like salt on the walls. 

Remember that rising damp originates from moisture under the ground, so can usually be found rising from the floors or skirting boards. You usually won’t find rising damp higher than a metre from the ground. It also mainly affects external walls.

Treating rising damp 

Most homes have a DPC: a damp-proof layer fitted at floor level to stop moisture from the ground seeping up into the walls and causing damage. These DPCs can get damaged over time, often as your house settles, and any cracks that appear can allow the damp to penetrate into the brickwork and rise up into the walls. 

Rising damp could have negative effects on plaster, wallpaper, floors and skirting boards. If left untreated it can lead to wet rot, a fungus that can damage wood. Or, even more seriously, it can cause dry rot, another fungus that spreads through wood very quickly and is sometimes referred to as ‘building cancer’. It can also lead to the growth of mildew or dangerous black mould that can cause a serious health risk to you and your family. 

Fixing the problem will probably mean quite a bit of work – the damp will need to be treated and the affected area damp-proofed to prevent reoccurrence. But the faster you can identify and treat it, the less expensive the work is likely to be. 

To treat rising damp, you may need to repair or replace the damp-proof course, but it’s a good idea to call in a damp surveyor to find out the exact cause of the problem before any work begins. Rather than installing a physical DPC, there are now chemicals and gels that can be injected into the walls to create a damp-proof membrane. A DPC injection is normally a much simpler process than trying to retrofit a physical DPC into an existing wall.

Does home insurance cover rising damp? 

It’s worth checking, but most insurance policies won’t cover you for damage caused by rising damp. 

You should also know that if your home has rising damp, you’re obliged to tell your insurance provider about any damage to the property. Failing to do so could risk invalidating your home insurance in the future.

Chris King 

From the Home team

“Condensation might be the most common cause of damp, but it’s also the most treatable. Reducing the amount of moisture in your home is the best way to combat condensation before it becomes a problem.

Simple things like opening windows or using fans while cooking, keeping lids on pans or making sure tumble dryers aren’t clogged with dust, could help to eliminate damp and mould.”

Penetrating damp 

This is caused by water from the outside of a building leaking through the walls. The most common causes of penetrating damp are leaking pipes, ageing brickwork and poor guttering.

Penetrating damp should be assessed and treated immediately to help minimise lasting or irreversible damage to your property.

Spotting penetrating damp 

Signs of penetrating damp include dark patches on the walls that won’t go away – they might even grow or darken when it’s wet outside.

Cold rooms, a reoccurring black mould that grows over time and a noticeable damp smell may also indicate that you have penetrating damp. 

From the outside, signs of leaks or cracks in your guttering or roof tiles may point to an issue. It’s important to stay on top of maintaining the outside of your property to save yourself from lasting structural damage.

Treating penetrating damp 

You’ll need to identify how the water is getting into your property and fix the source of the problem. Otherwise, any repair work you do on the inside will only be a temporary fix. 

If you can’t find the source of the leak yourself, you may need to hire a builder or a plumber to help. If your home insurance policy includes trace and access cover it may cover the costs of this. Once the source of the problem is fixed, you can begin to assess the damage on the inside. 

The problem with penetrating damp is that a lot of the damage may be affecting the walls themselves and so might not be visible. It’s usually advised to get a qualified damp surveyor in to investigate any damage that might be out of sight.

Does home insurance cover penetrating damp? 

Depending on the source, you might be able to claim for at least some damage in the case of penetrating damp. 

For example, while deteriorated piping would be considered ‘wear and tear’, if the source of the leak that caused the damp was a defective boiler, you may find that you can claim at least for damage directly caused by the leak. 

If you’ve identified penetrating damp, contact your insurance provider for more guidance. Remember, you’re obliged to tell your insurance provider about any issues relating to damp, whether your insurance covers you for the damage or not.

Frequently asked questions

How do I know if my home has a damp-proof course?

If your home was built in the last 150 years or so, it probably has a damp-proof course (DPC). Historically, builders used slate, but in more modern buildings it might be a plastic membrane. You can check if your house has a DPC by looking at the external walls. Close to the ground, between three inches to two feet up - depending on your home - you should see a thin dark line running horizontally between the brickwork all the way around the external walls.

What are the health risks of damp and mould?

According to the NHS, you’re more likely to suffer from respiratory problems, allergies and asthma if you live in a house that has damp and mould. Vulnerable people, including babies, elderly people, anyone with skin or breathing conditions and those with a weakened immune system, should avoid spending time in a damp and mouldy house.

What is dry rot and how do I identify it?

Dry rot is a fungus that destroys wood and timber. It infects moist and damp wood, but it can also move through other building material. It can cause serious structural damage to your property, so you should identify and treat it as soon as possible. Here are some signs of dry rot to look out for: 

  • wood and timber start to shrink, darken/turn grey and crack
  • there’s a damp or musty smell
  • timber becomes brittle to the point where it crumbles in your hand
  • large mushroom-like fruiting bodies start to form
  • patches of rust-coloured spore dust form around the mushroom-like growths.

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