What is rising damp?

Worried you’ve got rising damp? Here’s everything you need to know about it: how it’s caused, what to look out for and – most importantly – how to treat it.

Worried you’ve got rising damp? Here’s everything you need to know about it: how it’s caused, what to look out for and – most importantly – how to treat it.

Chris King
Head of Home Insurance
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Posted 9 SEPTEMBER 2021

What is rising damp? 

There are three main types of damp – condensation, penetrating damp and rising damp. Rising damp is when excess moisture in the ground travels upwards through tiny capillaries in your brickwork.

If you suspect you have rising damp, it’s best not to ignore it. Left untreated, rising damp can damage the foundations of your house. It can also cause wet rot and even dry rot, both of which can be extremely expensive to fix.

What causes rising damp? 

Excess moisture caused by issues like blocked drains and broken pipes can cause rising damp in your external walls

You can also get rising damp if your house doesn’t have a damp-proof course – a waterproof barrier that protects the brickwork. Or it may be that the damp-proof course you have is old and no longer fit for purpose.

What are the signs of rising damp? 

You won’t always see rising damp, but you’ll probably smell it. Damp has an unmistakeable smell that hits you when you enter a room. If you smell damp in your home, you should always investigate the cause. 

If rising damp has really taken hold, you’re likely to see it. It could be that your plaster and paintwork bubbles. You may see a ‘tide line’ of staining, damp patches on the wall or your wallpaper might start to peel. If it gets really bad, you may even see black mould on the walls and your skirting board could start to rot. 

It’s worth remembering that not all damp is rising damp. If your damp is patchy and more than a metre from the floor, it’s more likely to be penetrating damp.

Is rising damp a myth? 

There are some people who say that rising damp doesn’t exist. While that’s incorrect, rising damp isn’t as common as you might think. Certainly, there are unscrupulous tradespeople out there who’ll try to sell you an expensive damp-proof course you don’t necessarily need. That’s why it pays to do your due diligence and get a few quotes before committing.

Rising damp on internal walls 

Rising damp is usually a problem affecting external walls – it’s rare to find it on internal walls, unless one side is external-facing. That’s because most internal walls are partition walls, which means they don’t have any connection with the ground below. 

That’s not to say you won’t ever find damp on internal walls. But, if you do, the chances are something else is causing it, such as condensation from the bathroom or kitchen, or wet laundry.

Is rising damp a serious problem? 

Spotting a damp patch on the wall can be a panic-inducing experience, as you contemplate how much it’s going to cost to fix. Each case of damp is different, though, so you’ll need to get an expert in to assess the damage and give you professional advice. 

A word of warning: it can be tempting to go for a cheap-fix solution, like painting over the damp. But this could end up being more expensive in the long run, as you’re not addressing the root cause of the issue.

Should I buy a house with rising damp? 

If you’re looking to buy a fixer-upper, you’re likely to come across one with damp issues. So, should you buy it – or run a mile? The difficulty is that unless you’re a professional, you won’t know the extent of the damage. 

This is why it’s worth paying extra for a detailed survey. That way you’ll get an idea of how bad the damp is and how much it will cost to fix. If it’s going to be expensive, you can always try to negotiate a discount with the seller.

How to treat rising damp in an old house 

Rising damp can be a problem in older houses if they haven’t been properly maintained. If you suspect you have rising damp in your period property, call an expert in to make an assessment. It may be that you need to get a new damp-proof course.

Frequently asked questions

How can I treat rising damp?

A popular treatment for rising damp is a chemical damp-proof course. This is injected into the walls and stops any moisture rising. It’s a highly specialised treatment, so always have a reputable firm carry it out. 

But sometimes the moisture in your wall just needs somewhere to escape. On an internal-facing wall, you can provide this by making a tiny incision through the plaster above the skirting board. If you finish your walls in lime plaster or vapour-permeable paint, they’ll be less vulnerable to humidity.

Can I claim for rising damp on my insurance?

Each policy will be different, but it’s unlikely that your buildings insurance will cover rising damp. Insurance providers tend to see it as a sign that the building hasn’t been well maintained.

What happens if I don’t treat rising damp?

If you don’t treat rising damp, it can develop into wet or dry rot.

Wet rot is a fungus that can cause decay in wood. It tends to stay around the source of moisture, rather than spreading to other places. Although wet rot isn’t as serious as dry rot, it can cause structural damage if left untreated.

Dry rot is also a fungus that can spread through the wooden structure of your home, gradually destroying it. It can spread extremely quickly – even to neighbouring properties. That’s why, if you think you have it, you need to act quickly.

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