bad damp problem

If you are a new homeowner, you may not have heard of damp before or indeed Damp Hero. Damp is the build up of moisture on your property. It occurs when there is either a rapid rise in the amount of moisture entering the building or a slow local build-up of moisture exacerbated by its failure to disperse.

What is damp?

Damp appears as a dark spot on your walls or ceiling, with moisture visible on the affected walls or ceiling, depending on the severity of the issue. It is often accompanied by

  • Musty smell
  • Mould growth: specifically black mould growth, which will appear as grey growths or black speckled marks
  • Damp patches
  • Cold spots and cold walls
  • Condensation on cold surfaces such as windows has increased
  • Wallpaper that has been aged by water and is peeling or lifting
  • Paint that is flaky and discoloured, with blisters or air bubbles on occasion
  • Crumbling plaster that breaks apart.
  • Wood that is spongy and rotting
  • Rust amounts have increased around even recently installed metal fixings and fittings.
  • Brickwork that is crumbling or without mortar between exterior bricks
  • Discoloured or stained areas, brown patches or black spots 
  • Peeling wallpaper

NB: Mould may pose serious health concerns. People who live in mouldy conditions often complain of respiratory issues.

Breathing difficulties, a tense chest, coughing, and wheezing are also possible symptoms. These signs are generally moderate, but if you are exposed to mould spores for an extended period of time, they can become chronic.

Once you have spotted damp signs around your home, then it's time to contact a professional. Serious damp problems may require that you consult a qualified surveyor to give you a quote on how much it will cost you to treat the damp. The good news, though, is that treating a damp wall is easy and will take little to no time.

Types of damp

There are three main types of damp:

Rising Damp

It is a type of dampness that occurs when ground water rises up your walls. The ground water rises through the brickwork through capillary action.

Lack of appropriate damp-proof course often results in rising damp. It is a form of waterproofing that prevents water from penetrating your internal walls by capillary action in the external bricks. Another cause of rising damp is a damaged damp proof course.

Although penetrating damp spreads horizontally in your home, rising damp spreads vertically across interior walls, moving from the floor to half-way up the wall and, in some cases, all the way to the ceiling. External walls, just like internal walls, may be affected by rising moisture.

The damp proof courses may fail over time, especially in older houses. However, in most buildings, it may remain intact, but bridging may occur. This is where damp rises from the ground level, causing damp walls.

Examples where this may happen include:

  • Solid walls
  • External or internal renders
  • Intersecting stone structures
  • Raised external ground levels past the damp proof membrane
Identifying Rising Damp on walls

The tell tale signs of rising damp are:

  • Mortar cracking between bricks or stonework
  • Salt deposits that form when salts that are deposited on the internal walls evaporate.
  • Tide marks on interior and exterior walls
  • Dark patches that are damp to the touch


Condensation occurs when moist air comes into contact with a cold surface. The excess moisture in the air condenses on cold surfaces, such as walls, resulting in the formation of tiny water droplets. It can be attributed to ventilation problems; as a result of lack of constant air flow in the property.

It's mostly caused by showers or cooking steam that cannot escape. Most damp walls in modern buildings are a result of condensation. It affects

Penetrating damp

Penetrating damp, also known as lateral damp, occurs as a result of water seeping in through the external wall and into the house. It's usually caused by structural problems in a building, such as faulty guttering, defective building material or porous walls.

If left untreated, it can cause further deterioration to the fabric of your home, including damage to ceilings, floors and walls. It can also cause rot to timbers. The damp gets worse with heavy rainfall, especially if you have defective renders or gutters.

You can find signs of this type of damp where the external level of the ground is higher than the internal one. Basements and cellars are also common areas. The first signs usually are a wet patch that grows as water continues to leak in and mould.

How do you treat damp walls?

Now that you figured out that the problem behind the damp smell could be the various types of damp we've discussed. Walls are the most common places to find damp problems and therefore should be the first step in treating damp.

Below are some helpful solutions and pointers when dealing with damp on internal walls.

Treating rising damp

Here are the ways you can treat rising damp.

Install a new damp proof course

Getting a new one may cost around fourteen hundred pounds. The cost depends on the size of your walls, the kind of damp you have and the extent of the damage.

Damp proofing

This may involve the use of damp proof cream. It's among the most effective and economical ways to treat rising damp is with a damp proofing injection cream. It's made of water and silicon and contains highly concentrated ingredients designed to treat rising damp. The cream penetrated the mortar bed and into the bricks, forming a permanent barrier.

Treating penetrating damp

Stormdry Mason Protection Cream

Using a masonry protection cream such as Stormdry can help prevent rain penetration. It acts as a suitable render and protects against damp without affecting the visual appearance of your brickwork.

Carrying out repairs

A simple solution to fixing damp is repairing broken parts as soon as the damage occurs. Damaged windows are notorious for allowing water to seep through, so ensure you fix any broken parts. Also, make sure the drip grooves on the window wills aren't blocked or broken.

Don't forget to unblock gutters and drain pipes.

Replace damaged or broken bricks

Bricks eventually get damaged as time passes. Once they become porous, it's time to remove and replace them. You will also need to replace other parts such as plasterwork and rotting timbers.

Treating condensation

Improve ventilation

Sometimes a condensation problem may be so severe that you will need professional help. This may require electric ventilation, such as an extractor fan. Installing air vents through internal walls or sealed chimneys will help improve air flow in your house.

Adding ventilation vents to the top of your window frames will also help combat your damp issues.

Adjust your heating and insulation

Sometimes the central heating in your home may contribute to an increase in damp walls around your house. Sudden rises and drops in temperature can exacerbate the problem. Having your heating on a constant low will help reduce damp air.

Consistent insulation also helps in treating damp. Consider installing a cavity wall or loft insulation. Be sure to get a professional to do the job since some cavity walls can be the cause of damp, though it's a rare occurrence.

Double-glazed windows

Energy-saving measures that reduce ventilation in old buildings such as double-glazing increase damp. Double-glazed windows let in too much cold compared to single-glazed ones, making them more likely to allow moisture droplets to form.

How can I stop damp getting worse?

Reducing excess moisture

A great way to reduce moisture and damp air is by opening windows. Invest in vented tumble dryers. They use a hose to extract water and moisture and should be placed near enough to an outside wall or window for the hose to reach through.

Fix any leaks

Leaks from washing machines or dishwashers contribute to the formation of rising damp. Regular maintenance minimizes this risk.

Mould control

Here a few tips on how to treat rising damp on internal walls and prevent mould growth:

  • Dry wet areas as soon as possible
  • Keep the humidity levels in your home to a minimum by investing in a dehumidifier
  • Wipe down all surfaces prone to getting moisture
  • Position furniture a few centimetres away from external walls for ventilation

Below are some helpful for those who already have it and want tips on how to remove mould:

  • Fill a bowl halfway of water and a gentle detergent, such as dishwashing liquid or a hand-washing soap
  • Carefully clean the mould off the walls with a cloth soaked in soapy water. Brushing it will spread mould spores, so be careful not to do so
  • When you're done, wipe the moisture off the walls with a dry rag, then stick the rags in a plastic bag and throw them away
  • To remove any spores, all surfaces in the room should be properly washed with either wet cleaning or vacuuming.

Damp proofing walls

Damp proofing walls involves installing a damp seal to prevent damp patches from expanding. A damp seal is a type of paint designed to protect against damp walls. Internal walls should be warm and dry to touch if there is no rising damp.

Quick reminder: Damp proofing should not be used as an alternative to fixing a damp wall.


Damp is a common issue in many homes. There are three varieties: rising damp, condensation and penetrating damp. Common signs that you might have damp on your walls include:

  • rotting wood
  • damp spots
  • a musty smell
  • cold walls
  • blistering wall paper

It occurs on interior walls but can even extend to external walls. Contact Damp Hero today for technical advice and more information on how to treat damp.

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