Condensation, damp, and mould: what’s the difference and how do you get rid of them?

Are you worried about early signs of damp and mould in your home? Some types of damp are more serious than others. Learn what damp looks like and how to treat it with our simple guide.

Written by

Helen Phipps

Insurance comparison expert

Reviewed by

Rachel Lacey

Insurance and money expert

Last Updated

17 NOVEMBER 2022

10 min read

What causes dampness in a house?

Damp in a house is caused by an excess of moisture on internal walls and surfaces that has no way of escaping. The most common form of dampness in a house is condensation. Condensation forms when warm air inside a building meets a cold surface like a wall, window or even furniture and leaves drops of water on the surface.

Condensation is commonly caused by steam build-up from hot showers, drying clothes inside and, of course, cooking. If there’s no way for that excess moisture to escape, it could eventually lead to damp and mould problems.

And while condensation build-up can be easily wiped away, other causes of dampness in a house can be more serious and difficult to treat, for example, leaking pipes, rising damp in cellars and on ground floors, or water seeping in through a damaged roof or window frames.

Read our guide on spotting the different types of damp, the best way to treat them and what types of damp damage may be covered by your home insurance.

What is condensation damp?

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.

How to stop 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.

So, how do you get rid of condensation in your home? Here are some easy steps you can take:

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 windows 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, especially during the colder months
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 damp?

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.

Did you know?

While you sleep at night, you’ll breathe in and out thousands of times. On a cold night, the moisture from your breath can form condensation on your bedroom windows. These droplets of water could eventually pool on the window sills and seep into your walls and frames. To help prevent damp patches and condensation mould in your bedrooms, wipe down your windows and open them up each morning to let excess moisture escape and the fresh air in.

What is 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.

What does rising damp look like?

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

Peeling paint or wallpaper, along with mould growth on 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 won’t usually find rising damp higher than a metre from the ground. It also mainly affects external walls.

How to fix 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 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 could lead to wet rot, a fungus that can damage wood. Or, even more seriously, it could cause dry rot, another fungus that spreads through wood very quickly and is sometimes referred to as ‘building cancer’. It could also lead to the growth of mildew or dangerous black mould that could cause serious health problems for 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.

Rising damp treatment may include repairing or replacing 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.

Is rising damp covered by insurance?

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.

Helen Phipps

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.

Penetrating damp signs

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.

How to fix 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 advisable 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 could 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.

What causes mould on walls?

Condensation and damp issues, if left untreated, could result in mould growing on the walls of your home. Mould is a type of fungus that thrives in damp and humid conditions, that’s why it’s often found in poorly ventilated bathrooms and kitchens. Mould grows rapidly and will continue to spread over walls, ceilings, skirting boards and even furniture, until it’s removed and treated. It can be a serious health risk, so take action as soon as you spot the first mould patches forming.

Signs of mould

Mildew is a type of fungus that is often found in bathrooms and cellars. It’s typically white with a fluffy appearance and can be easily wiped away with an over-the-counter cleaning product.

Mould, on the other hand, is a far more aggressive type of fungus. Typically black or green in appearance, not only does mould look unsightly and smell unpleasant, but it can also release toxins if left untreated. This could be a serious health risk, especially for asthmatics, the elderly and young children.

How to get rid of mould

Mildew can be easily removed with a scrubbing brush and an over-the-counter cleaning product. Mould, however, needs to be treated with a specialist product that will kill the fungus, not just wipe it away. While anti-fungal products are widely available to buy, it may be best to call in the professionals, if your mould problem is widespread.

If you decide to treat mould yourself, make sure you wear protective googles, rubber gloves and a facemask to protect you from the mould spores.

And, if mould has affected your carpets, and can’t be removed, it may be best to rip them out and throw them away altogether.

Does home insurance cover mould?

As most home insurance policies exclude damage caused by damp and condensation, it’s unlikely you’ll be covered for mould problems. The best way to protect your home from mould is to prevent it from growing in the first place:

Let in as much natural light as possible during the day
Clean, vacuum and dust regularly to prevent fungus from growing
Keep rooms well-ventilated to ensure moisture can escape
Ensure your home is well-insulated to help keep humidity levels low during the winter
Consider buying a dehumidifier to help remove excess moisture from the air.

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 could 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: