How to get rid of damp

‘Damp’ is a general term which covers a range of different issues connected to excess moisture.

Moisture in the air will form condensation (droplets of water) when it hits a cold surface, like a window. Most of us will see condensation on our windows from time to time, for example on a cold morning. This isn’t necessarily a problem if it clears up quickly.

The UK’s cool, wet climate contributes to the problem, but building fabric also plays a part. It’s not just older buildings where damp happens: new homes can suffer from damp too.

Problems start if the moisture in a home builds up to the point where it starts to cause damage or mould growth. If it’s building up somewhere other than on the window, you might not notice until wallpaper starts to peel or black mould starts growing.

Rising damp

If you see a tidemark of damp occurring at the bottom of a wall, the issue is likely to be rising damp. This is where ground water moves up through the house due to damage to a protective barrier known as a damp-proof course.

Penetrating damp

This is where water seeps through walls from the outside. This can happen due to structural problems like faulty guttering or roofing and can get worse when it rains. It usually shows up as a concentrated damp patch on surfaces.

Damp is more likely to happen in places that are colder than the rest of the house. This includes exposed corners or where there is a gap in the insulation.

It can also happen in places where the air can’t circulate freely, such as behind furniture. Rooms that tend to have more moisture (such as kitchens and bathrooms) can be prone to mould if there isn’t proper ventilation.

Moisture can get into your home in several ways:

• Rain can get in through leaking roofs, blocked or damaged guttering, leaky walls and poorly fitting doors and windows.
• Leaks from plumbing faults, failed appliances and poorly sealed baths and showers can quickly build up, often where you can’t see them.
• Ground water can rise through the walls and floor if the dampproof course isn’t working properly. This is called rising damp and can be a serious issue.
• We all create moisture in our homes through cooking, boiling kettles, showers and even breathing.
  • Typically a household produces up to 100 litres of moisture a week. This can vary depending on the size of your home, lifestyle and appliances. If this moisture isn’t removed through ventilation, it’ll build up on surfaces or stay in the air.

If you don’t have any leaks or rising damp issues, then the problem is almost certainly condensation.

Damp can show in different ways, but common signs of damp include:

• excessive condensation build-up around windows
• black mould
• musty smells
• damaged skirting boards or floorboards
• crumbling or stained plaster
• peeling paint or wallpaper
• tidemark running along the bottom of a wall
• damp patch showing up on surfaces

Living in a damp property can lead to serious problems as well as generally being unpleasant.

Damp often leads to mould, which can be a risk to the health of people living in a home. Mould can cause symptoms like nasal stuffiness, wheezing, and eye or skin irritation, among other issues.

Children, older people and people with skin or respiratory conditions are particularly at risk from moisture build-up in the home.

If you do have mould growing, it’s important to remove it properly and as soon as possible to minimise any health risk.

If left untreated, excess moisture and damp can cause problems in your home. As well as the signs of damp we’ve discussed (such as peeling wallpaper, damaged skirting boards, etc), damp can lead to:

• rotting wood or timber frames
• weakening walls, floors or foundations

There are some simple ways of cutting the risk of condensation build up and reduce the moisture levels in your home.

Prevention is a great first step to avoiding damp. By making a few small changes, you can reduce moisture build up in your home. These include:

• Covering pots and pans with a lid when cooking.
• Drying clothes outside when the weather is warm or dry.
• Wiping down the walls with a squeegee or towel after showering. You can do the same for windows.
• Considering to buy a dehumidifier for dealing with excessive moisture or to help with drying washing inside.

Air needs to flow in and out of your home to keep it fresh, dry and healthy. Ventilation is essential to reduce moisture. You can improve your home’s ventilation by:

• making sure trickle vents are always open and clear of obstructions and
• opening windows several times throughout the day for at least five minutes. If you can, leave them open for longer.
• using extractor fans (if you have any) and letting them run for at least 15 minutes after taking a shower or a bath.
• using a cooker’s extractor whenever cooking and letting it run for at least 15 minutes after finishing cooking.
  • if you don’t have extractor fans or a cooker extractor, then open a window while showering, having a bath or cooking. Again, leave open for at least 15 minutes afterwards.
• installing ventilation measures such as air vents or ventilation tiles.

Generally, a home that isn’t heated properly can contribute to damp issues. Rooms where the heating is turned off or low during colder months are prone to damp problems. In this case, you might need to improve the ventilation in the room or turn the heating up from time to time.

However, leaving heating on all the time just to avoid damp isn’t a sensible solution. This would use a lot of energy and cost a lot of money. Having an efficient heating system and appropriate heating controls is an excellent starting point to keep your home dry and comfortable.

• Make sure air can circulate throughout your home by leaving internal doors open where possible.
• Ensure there is a gap of at least 10mm underneath internal doors so air can circulate between rooms at times when doors are closed.
  • This means 10mm between top of floor covering (eg carpet) and bottom of the door when closed.
• Leave gaps between furniture and the wall.
• Avoid cold spots: there may be gaps in wall insulation for example. This may be because:
  • There’s a problem with the installation.
  • The cavity wall insulation has slumped in the cavity leaving a gap at the top of the wall near the roof. Try to get insulation defects like this fixed as they can attract condensation and mould.
• Don’t fit any new draught proofing in a room that doesn’t have enough ventilation or where there’s already a condensation problem. If you’re getting a professional to fit insulation, draught proofing or new windows or doors, ask them what measures they’re including to maintain good ventilation.

To truly get rid of damp, you need to address the root cause of the problem. If you have rainwater getting in, or any internal leaks or signs of rising damp, it’s important to get the problem sorted out quickly.

You’ll usually need a professional to come in and advise you. You should get quotes from three TrustMark-certified professionals to make sure you find the best value. TrustMark is a government-backed quality assurance scheme for work carried out in or around your home.

If you have mould form in your home, it’s important to get rid of it as soon as possible.

You should use an antifungal cleaning product or a product that’s designed to kill mould. Use a disposable cloth and throw it away after use to avoid spreading the mould.

Never touch the mould directly. Remember to wear gloves and a mask when cleaning the mould. You should also wear any other personal protective equipment that the product’s manufacturer recommends. This will be listed on the label.

You should only wipe mould when it’s wet, not when it’s dry. This helps avoid spreading the mould spores into the air.

Make sure the area you’re cleaning is well ventilated by using extractor fans or opening windows. Keep doors to other rooms closed: this will help avoid spreading mould spores in the air to other parts of the house.

The relationship between insulation and damp is complicated.

Insulation keeps a house warmer by reducing heat loss. Condensation is less likely to build up on a warm surface, so insulating a whole property reduces the risk of moisture build-up.

But if you find condensation in one place, it might be because it’s an uninsulated part of the house. This could be if your wall is insulated but you have single glazing windows, for example. Another common issue is an insulation gap in a wall (usually at the top of wall), as small gaps tend to attract condensation.

Insulation shouldn’t cause damp issues if your home:

• is suitable for insulation
• has the right type of insulation
• the insulation has been installed properly

However, sometimes insulation can expose damp problems that already existed.

For example: if you had a leaky roof before installing cavity wall insulation, water could’ve been leaking down the cavity. When the cavity was filled, the water must go somewhere else, exposing a problem that was there all along. This is why it’s crucial to resolve the root cause of damp.

Find out more about cavity wall insulation and potential dampness issues.

Adding insulation may reduce air leaking through walls, floor or ceilings. This also reduces the natural ventilation of your home, so additional ventilation will need to be considered by the installer. This might mean installing one or more extractor fans or other suitable ventilation measures.

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