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Avoid spending thousands on damp-proofing

Before you splash out on costly professional damp repairs, make sure you follow our top tips for identifying and solving damp yourself

Avoid spending thousands on damp-proofing

Serious damp issues can cost as much as £16,000 to rectify. But, thankfully, there’s a lot you can do to identify and fix the problems yourself, before resorting to professional help. 

From droplets of condensation on your window panes to crumbling skirting boards, peeling wallpaper and unsightly patches, damp problems have many different symptoms.

The video below reveals the things you should know about damp – and the steps you can take to prevent or fix it yourself.

Can’t see the video? Head to Which? to view this page in full.

Keep reading for a more in-depth look at the types of damp that might be plaguing your home. For our detailed rundown of the potential problems and solutions, visit our guide to dealing with damp.

Types of damp and how to treat them

There are three main types of damp: condensation, rising damp and penetrating damp.

But damp isn’t always clear cut – you may have two types that are intermingling, or different types in different areas.

Condensation problems

A very common form of damp, condensation occurs when warm, moist air inside your home comes into contact with colder surfaces, often windows and exterior walls, and releases water in the form of droplets. If the moisture isn’t removed, mould can quickly grow.

Problems with condensation tend to occur when a building has a high moisture content, often due to a lack of adequate ventilation.

There are five simple, cheap condensation solutions:

  • Wipe away condensation as often as you can to keep surfaces dry. A cloth will do the job, but you can also buy specialist window vacs. We’ve tried out the Karcher Window Vac WV 5 Plus.
  • Control humidity levels. Cooking, showering and drying laundry all release lots of moisture. Install extractor fans in these rooms, and keep the doors closed while the fans are on to help them work more efficiently.
  • Ventilate your home. If possible, add air vents, including air bricks, window vents, roof ventilation tiles and ventilated sofits. Failing that, open the windows as often as you can.
  • Keep your heating on at a constant but slightly lower temperature. Whacking your heating up when the house is freezing can contribute to damp problems.
  • Consider buying a dehumidifier – they’re a cheap way to draw moisture out of the air. Visit our dehumidifier reviews to find one that does the job quickly and quietly.

For more advice, read our dedicated page on how to stop condensation.

Dehumidifier next to a dog

Penetrating damp problems

Penetrating damp appears where walls and joinery are subject to concentrated, prolonged wetting. Externally, this can come from poorly maintained rainwater fittings, leaks in your roof, or hairline fractures in pointing or render. Internally, it might be caused by overflowing baths, sinks or shower trays, cracked or damaged tiles or burst pipes.

The result is unsightly patches of damp on walls and ceilings, as well as peeling wallpaper and paint. These patches often darken when it rains, and they usually spread horizontally instead of vertically.

While you may find that your home needs extensive work, some basic maintenance can go a long way to curing or managing a damp problem:

  • Clear overflowing gutters. Overloaded gutters can force water to spill down your walls.
  • Locate and mend leaking pipes. Look for leaks from which water is escaping on both internal and external pipes, which can rust through at the back.
  • Fix roof problems, wall cracks and window damage. These can all let excess moisture into your home.
  • Replace old bricks that have become porous, or paint with an exterior silicone water-repellent paint or limewash.
  • Clear wall cavities. If walls are consistently getting damp, it may be that debris lodged into the wall cavity is providing a direct route through to the inner walls.
Fixed crack in wall to prevent penetrating damp

For more details, head to our dedicated page on how to get rid of penetrating damp.

Rising damp problems

Rising damp is quite rare, but it’s one of the hardest types of damp to fix. It tends to be caused by moisture below the ground that creeps up to your floors and can rise up your walls. It can cause crumbling skirting boards, tide marks on walls and mineral deposits that leave a white, powdery substance on walls and floors.

The most important thing is to make sure your building can breathe. While it may be tempting to completely waterproof your floor to seal it off, this can exacerbate a damp problem as, with nowhere to go, the moisture will soak up the walls instead.

To treat rising damp, you may have to call in the professionals. But there are some things you can check and do yourself first:

  • Check your damp-proof course. It should be at least 15cm above ground level. If it’s not, see if you can lower the floor level outside yourself.
  • Make sure your walls can breathe. Hard cement render or pointing will trap moisture from the ground in your walls, while breathable lime-based mortar will allow them to dry out naturally.
  • Paint over small damp patches underneath the floor covering with two coats of bitumen latex waterproof emulsion, which you can buy from many DIY stores.

Visit our dedicated page on how to deal with rising damp for more.

Paying for damp proofing

Damp can be a complex issue, and it may be that your home is being affected by more than one type. Plus, trying to solve one problem can sometimes create another.

If the solutions above don’t seem to help, it may be time to call in a professional. We’d recommend asking three companies to assess the problem, make suggestions for repair work and give you a quote, as professional solutions and costs can vary.

Testing damp

Meeting a few tradesmen should help you choose what the best course of action is for your home.

You can visit Which? Trusted Traders to find a recommended damp specialist in your area who has been through our rigorous checks.

To help you ascertain whether a quote you’ve been given for a job is roughly right or way off, we’ve worked with the Royal Institution of Chartered Surveyors, which publishes average costs for building work and repairs.

We’ve looked at costs for everything from clearing blocked wall cavities and lowering the floor below the damp-proof course, to inserting a new damp-proof barrier and coating walls and ceilings in a damp-proof material. Visit our page on damp costs to find out how much you should expect to pay for these treatments.

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