Got a damp patch on your wall that seems to be creeping up from the floor? It could be rising damp.
But this serious form of damp is misunderstood and often misdiagnosed. Either way, it's a homeowner's nightmare.
If you don't treat it, it can cause structural damage to your home, which could be expensive to fix. It can also make heating your home tricky and just generally uncomfortable.
In this guide, we'll look at what rising damp actually is, how to spot the early signs, and what to do if you think you've got rising damp.
What is rising damp?
Rising damp is moisture travelling up your walls from ground level.
The porous nature of your walls sucks up extra moisture like a straw. This is called capillary action, if you want the technical terminology.
It's not too tricky to spot - it's a damp patch on your wall that starts at your floor and rises up to a certain point.
Rising damp causes dampness in rooms, staining, and can even affect your building's structure. It's generally more common in older homes. Here's what can cause rising damp:
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Issues with your damp proofing
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Internal issues with your wall
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Leftover material in the cavity wall
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A new external feature that's affecting drainage, like a new patio
Rising damp is different to condensation. Condensation is moisture in the air that becomes liquid water when it's cooled. It's usually caused by a lack of ventilation.
There's also penetrating damp - this can hit anywhere on your walls, and it's usually caused by damaged brickwork. Rising damp is different because it works its way up from ground level.
It's common for both of these types of damp to be misdiagnosed as rising damp. So make sure you get a professional in if you notice signs.
What causes rising damp?
Rising damp is caused by excess moisture at ground level.
But there are a few reasons why it can start travelling up your walls. The main reason could be that you don't have an effective damp proof course, or DPC. For example, in older homes the damp course can degrade.
Your damp course might have been bridged too. This means something's come into contact with the DPC and blocked it or risen above it, so moisture gets in.
Anything that blocks or bypasses your DPC is a one-way ticket for damp. For example, a new patio might block your DPC, so moisture seeps into your wall. Because the DPC is blocked, the moisture hasn't got anywhere to go.
Groundwater causes rising damp too. This is when the water level rises to a point where it saturates the soil, either due to heavy rain over a long time or flooding.
Because the water doesn't drain away, it seeps into your home's walls.
Is rising damp dangerous?
Rising damp can cause mould, which has health implications. It can affect your breathing and trigger allergies.
Cosmetically, it can damage plaster, wallpaper, painting, skirting boards and your belongings. It can damage your home's structure too, if it gets serious.
Dealing with this can take its toll. In fact, damp is linked to higher levels of depression and anxiety because people have to deal with fixing it.
Not only do you have the disturbance of the work, but it's the cost too. If you suspect you have rising damp, look into it as soon as you can so the problem doesn't get worse.
How can you check for rising damp in your home?
Here are the signs of rising damp:
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Damp walls and skirting boards - this might be an early sign of rising damp
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Wallpaper that looks like it's bubbling
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Tide marks - this is the mark that's left behind from the water rising up the wall
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Peeling paint
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A musty smell
You could also try getting a moisture metre - this measures the amount of moisture in the wall. But they're not always accurate, so just use it to check before calling in the experts.
If you think you've got rising damp, get a specialist involved. It's common for it to be misdiagnosed by inexperienced people.
How to treat rising damp
First, you need to get a specialist damp surveyor to help you work out if you do have rising damp. They might take these steps if you have it:
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The damp specialist might strip the wall material (wallpaper, plaster, etc.) and repair the existing DPC. They might even install a new DPC, depending on what state it's in.
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Sometimes specialists install a chemical DPC. This involvles injecting silicon into the walls and brickwork so it's water repellent.
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Dry rods are another option for treating rising damp. These are inserted into holes that are drilled at regular intervals. Over time, the rod dissolves and spreads its materials to the bricks and mortar, creating a moisture-repelling barrier. Usually, this is a silane or siloxane-based cream.
Because the whole wall is stripped, be prepared to replaster and repaint your wall. In some cases, your damp expert might put in a waterproof cavity wall membrane to help with salt migration and to help the plaster dry.
There's a big caveat though: the rising damp treatment you get varies depending on the type of house you have and the treatment you need.
What are the risks of leaving rising damp untreated?
Rising damp isn't good. It can cause damage to your home, your belongings, and most importantly, it's not good for your health.
Damp homes are also notoriously hard to heat. In the winter months, it'll probably be a balancing act between keeping your heat on low and leaving your windows open. So, your energy costs could creep up.
Getting an expert in as soon as you notice an issues means you can fix it before it develops. Potentially saving you money.
Keeping your home well-maintained is also normally part of your home insurance agreement.
How much does it cost to treat rising damp?
On average, it costs about £3,250 to fix rising damp. But it can be as high as £6,500.
But this varies depending on the type of rising damp treatment you're having and your home's structure.
For example, it'll cost more to fix rising damp in a detached home because there are more external walls.
Your damp proofing expert will need to get inside your wall too, so you'll have to replace the plaster and repaint the wall, which adds to the cost.
Does home insurance cover rising damp?
No, home insurance doesn't usually cover rising damp. That's because it's classed as 'wear and tear' and is a home maintenance issue.
What's the difference between rising damp and condensation?
Condensation is when moisture in the air meets a cold surface - like a window - and creates liquid water. It's caused by everyday things you do in your home, like cooking, showering, drying clothes indoors and even breathing (but don't stop doing that, please).
This is different from rising damp, which is caused by water at ground level.
If a home isn't ventilated properly, condensation can build up and cause damp patches, musty smells and even damage your belongings.
Sometimes, lack of ventilation can cause black mould. This looks like black or dark staining in the corners of the room or along the ceiling.
Black mould has serious health consequences, like respiratory issues, rashes, sneezing and coughing. If you have asthma or a weakened immune system, these symptoms could get even worse.
You can get rid of black mould using a specialist mould and mildew remover or bleach and water. Make sure you use gloves, a mask, protective eyewear and something to protect your skin when you're treating it.
Spray the solution onto the black mould and scrub thoroughly. Once you've cleared it, dry it as best you can. Use fans if you've got them and open the windows. A dehumidifier can help with this too if you have one.
If it's a serious black mould infestation, you should call a professional. Particularly if you have health concerns.
What's the difference between rising damp and penetrating damp?
Penetrating damp can appear anywhere on the wall, whereas rising damp seeps up from the bottom of the home.
Penetrating damp is sometimes caused by rainwater that travels through the walls or the roof, getting through either by defects in the building's structure or damaged brickwork.
Gutters and downpipes can also cause penetrating damp if they're blocked.
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