In your home, mold or mildew around windows and doors, musty smells, and discoloured patches on wallpaper and walls are all signs of damp. In this article, we look at how to identify the different types of damp. We also look at how to treat damp, damp proofing costs, and what to do if a homebuying survey shows signs of damp.

 

A guide to spotting damp in your home 

As soon as you notice dampness, you should take action. In the long run, it can cause serious problems in your home, especially if the dampness is in contact with structural timbers. A damp problem can lead to rot, which makes fixing it more expensive. Health problems can also result from living in a damp home. 

The most common signs of damp are listed below. If you see any of these signs, then it’s time to get it treated.

  • It smells musty and damp
  • A wall with patches of discolored paint or wallpaper
  • Water droplets on walls or windows
  • In the walls, floors, ceilings, or around windows, there are dark patches of mould
  • Skirting boards that have rotted or are damaged
  • When soluble salts dissolve, they leave a white residue on walls and floors 
  • A wall that feels cold to the touch
  • Wallpaper that lifts or peels
  • A higher level of humidity in the air

Types of damp

There are three types of damp: rising damp, penetrating damp, and condensation damp. Different types of damp require different treatments. 

1. Condensation

Condensation is the most common type of damp. Excessive water droplets running down the windows or walls or dark mould appearing behind furniture on external walls are signs of condensation.  

Condensation can be a problem for a number of reasons. Most condensation issues are caused by insufficient heating or inadequate ventilation in a property.

2. Rising damp

This type of damp is caused by external groundwater being drawn up through brickwork through what is known as capillary action.

It is possible that rising damp is causing moisture to build up at the base of the wall. There is usually a ‘tide-mark’ visible up to 1 m above floor level. The salts present in ground water may also result in salt marks on walls and plaster suffering from rising damp. 

In newer houses, a damp-proof course is typically built into a wall 15cm above ground level, and a damp-proof membrane is installed under the floor to prevent water from rising. Both are connected to provide a seal against water entering the house. However, many older properties were built without one or both of these types of protection. 

In many homes, these barriers can be damaged, worn away, or compromised over time by higher external ground levels. In the absence of these barriers, damp may start to appear on your walls or floors. 

3. Penetrating damp

Normally, penetrating damp is caused by external defects on the house that allow water to enter. External defects that may allow rainwater to penetrate a property or building include:

  • Roof coverings that are defective
  • Inadequately maintained rainwater system, gutters, drains, and downpipes
  • Rainwater system and wall surfaces affected by external vegetation
  • An external coating or render that is cracked or defective
  • Defective pointing and worn mortar joints
  • Masonry that is broken or permeable
  • The seals around windows and doors are defective

A defect’s severity will depend on its type. Leaking downpipes, for example, will likely cause a localised problem. If, however, the problem is porous brickwork, the problem will be more widespread and potentially more expensive to fix.

 

Getting rid of damp

Dealing with damp as soon as possible will make the process easier and cheaper. Your home will also be less likely to develop other problems as a result of the damp.  The longer you leave it, the more painful and expensive it is to fix.  

Any damp issue must be treated according to its cause. Due to the fact that there can be multiple causes, this may not be a straightforward process. Your damp problem may be treatable yourself, but if it is serious, you may need to hire a damp specialist.

 

Is damp-proofing a home expensive?

Several factors will determine the cost of damp-proofing your property, including its size, age, and severity. Some damp problems can be solved with simple changes, but others may cost significantly more.

Condensation issues:
A good quality extractor fan would cost over £500 to install.  In order to comply with building regulations, additional work may be required.

Tackling rising damp:
It would cost from £1,200 to install a remedial damp proof course and associated plaster works on a flat 5m wall. Depending on the property’s construction and accessibility, this may vary.

Fixing penetrating damp:
Fixing penetrating damp will depend on its cause. If the problem is caused by defective rainwater pipes, simple maintenance may solve it. It may be very costly to fix defective external coatings, however.


What you can do to prevent damp

The best cure is prevention. To prevent damp in your home, you can do the following: 

    • Keep your building’s exterior in good condition by performing regular maintenance checks 
    • Maintain gutters and roof tiles  
    • Keep an eye out for cracked or rusted downpipes
    • By drying clothes outside and keeping lids on pots when cooking, you can reduce the amount of moisture in the air
    • Keep window vents open and use extractor fans to improve ventilation
    • Allowing air to circulate between walls and furniture
    • Cleaning stone or brickwork that has grown moss or lichen
    • Walls with defective pointing need to be repaired


What should I do if damp shows up on a house survey? 

HomeBuyers Reports (level 2) or Building Surveys (level 3) are required if you suspect damp in a new house.  There is a test for damp in the walls in both of these surveys. The condition of the existing damp proofing will also be inspected during a full building survey.

In any event, you may not be able to identify the root cause of the problem without the seller’s permission to carry out an invasive inspection, which may include peeling back carpets and lifting floorboards. The survey may recommend further investigation in these cases.

After the survey is completed, speak with your surveyor.  If damp is found, you can ask them how much it might cost to fix the problem and get a few quotes from damp specialists. If you have these quotes, you can negotiate the price with the seller of the property or ask them to fix the problem before finalising a deal for the property. Make sure you see proof that the work is being performed by a registered tradesperson if this is the case.