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Damp is one of the more common and damaging problems we find when carrying out a building survey. All our chartered surveyors are equipped with a Protimeter, which measures the percentage of damp in various materials around the property. You will see our surveyors making a visual inspection of an area then taking readings at regular intervals.

In essence, damp is caused by the build-up of excess moisture within a building. It can be from either internal condensation or outside intrusion. Often, it can be blamed on poor build quality, inadequate building maintenance or the deterioration of the fabric of the building. Dampness that is left untreated can lead to other problems such as rot and fungal infection.

So, what are the types of damp we come across?


Rising Damp


Rising damp is a common term used to describe the movement of water from the ground up the walls. It occurs via capillary action. In basic terms, rising damp occurs when ground water travels upwards through porous building materials such as bricks and mortar. The absorption of water can damage the wall’s plaster, joinery, timber floors and decoration.

Rising damp can be distinguished by a tide line of yellow or brown staining, or blown plaster in the lower areas of wall above the skirting board. This is often combined with rotting skirting boards and flooring. The damp can reach heights of 1.2 meters before gravity takes over, but it can often ‘hide’ behind furniture.

Other signs of rising damp can include white, fluffy deposits in your plaster which may also be accompanied by black spots of mould.

Painting over damp will provide a quick visual fix, but it will quickly come through again. It needs to be treated by a specialist sooner rather than later.


Lateral Penetrating Damp


Lateral penetrating damp is normally found on walls below ground floor level, within a basement area for example, or where the walls hold back earth.  The damp patches and mould grow internally to basements and cellars below ground. The damp penetrates under hydroscopic pressure and can cause considerable internal damage.




Condensation is caused by high humidity, particularly during cold weather. Bathrooms with little or no ventilation are particularly susceptible due to the steamy conditions. It can be distinguished by black mould fungus, sometimes also called Aspergilla. This fungus is very damaging to property and is extremely bad in terms of health. It causes aspergillosis, chronic coughing, headaches, chronic fatigue and rashes.

Therefore, keeping areas such as bathrooms and utilities well ventilated is critical. Thermostatically controlled condensation units, passive vapour vents and extractor fans are all good ways to reduce the humidity.


Rain Penetration


As it suggests, rain can enter a property due to building faults or deterioration. The most common areas that can be affected are roofs, walls, chimneys, windows and doors. Overspill from gutters and downpipes can also be an issue if incorrectly maintained. Rain penetration can often be distinguished by green patches on the external walls of a property, or roof tiles laden with vegetation. Unfortunately, despite the eyesore, rain penetration often causes the most havoc within the structure.


Water Damage


Leaking plumbing, burst pipes, leaking roofs and actual flooding are all causes of water damage. The extent of any water damage will depend on the amount of water and length of time that it has been leaking. It is usually covered by home insurance, which can provide some relief to funding repairs.

Restoration after water damage will vary depending on the location and amount of destruction. Initially, dehumidifiers and drying fans will be installed to make restoration work easier when it commences. For those whose properties are affected, all saturated joinery and plaster will have to be removed. Then, it will be replaced using new pre-treated timber and a damp proof plastering.




If unattended, all damp issues can lead to attacks from various fungi, such as Dry Rot Fungus and the previously mentioned Black Mould Fungus. This will affect the health of those living in the property, and will lead to costly repairs.

If you recognise any of the types of damp mentioned above in a property, please get it thoroughly checked by one of our chartered building surveyors. A few hundred pounds spent now will identify the root cause of the problem and provide a solution to prevent it happening again.