Identifying damp in your property

Identifying damp in your property, building survey in Surrey, Hampshire & North London

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 and you will see our surveyors making a visual inspection of an area then taking readings with a protimeter at regular intervals over the area.

In essence, damp is caused by the build-up of excess moisture within a building, from either internal condensation or intrusion outside, and can often 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 wet or dry rot.

So what are the types of damp we come across;

Rising Damp

Rising damp is the common term used to describe the movement of water from the ground which rises up walls and other ground-supported structures 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 take over but it can often ‘hide’ behind furniture.

Other signs of rising damp can include white, fluffy deposits in your plaster – these are the salts which has been washed from your bricks and they may also be accompanied by black spots of mould.

Whilst painting over damp will provide a quick visual fix, it will quickly come through and will need 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 area being constantly steamy. It can be distinguished by Black Mould Fungus, sometimes also called Aspergilla. This fungus is very damaging to property, furniture, clothing and is extremely bad in terms of health; causing the Aspergillosis, chronic coughing, headaches, chronic fatigue and rashes.

Keeping areas such as bathrooms and utilities well ventilated is therefore critical. Solutions such as thermostatically controlled condensation units, passive vapour vents, and extractor fans can all be implemented to stop the issue developing again in the future.

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 and openings such as windows or doors. Over spill 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 most havoc from within structures, such as walls, which cannot be seen by the human eye and often only noticed when the damage has already been done.

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 but, 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 often 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 and 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. Repairing these can quickly add up and affect the health of those living in the property.

If you recognise any of the types of damp mentioned above in your property or spot one of them in a new home you are looking to buy, 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.

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