Rising damp describes the movement of moisture upward through permeable building materials by capillary action. Best defined as ‘the slow upward movement of moisture within walls and other ground supported structures’. (Hall and Hoff, 2007).
Mineral construction materials are open-pored: contact with water produces the capillary action. Large volumes of water can therefore penetrate the building’s fabric within a relatively short period of time.
Capillary action itself is caused by three forces: adhesion, cohesion and surface tension. Within a capillary that is experience rising damp, the adhesive water molecules are more powerful than the cohesive molecules, and the surface tension keeps the water as a body. The adhesive molecules are more attracted to other surfaces, in this case the capillary walls. This attraction, or adhesion, causes the water to rise up a capillary.
Pores and capillaries between 1μm and 100μm exhibit capillary action, resulting in water being transported into the building material up to a height of typically 1.2m.
- Failure of an existing damp proof course due to a deterioration of the materials that they were made out of, which is commonly felt or slate.
- A lack of any damp proof course being installed at the time of construction. Typically found within older structures within the UK, but as building regulations and practices vary, it may be seen in more modern properties around world.
- Ineffective drainage surrounding the property as well as a lack of sub-floor ventilation.
- ‘Bridging’ of the cavity wall as a result of debris or dirt.
- The accumulation of ‘moisture reservoirs’ in the foundations may also arise as the result of plumbing leaks or floods.
As well as being unappealing, rising damp can pose a significant structural issue to a building or home. The damp can compromise the external mortar of a building, as well as steel and iron elements. A damp environment within a wall allows organisms to grow. Internally, the damp can lead to mould on the walls surface, posing a potential health risk to the occupiers.
The most common indication that rising damp is present is a line of dampness across a wall, referred to as a ‘tide mark’. Rising damp may also cause wallpaper, render and paint to flake away from the area in question. Salt deposits are also likely to exist in an area that is damp.
A damp environment often has a recognisable musty, or damp smell, as well as the area being cold to the touch.
If left untreated, rising damp has the potential to cause vast amounts of structural damage to a property. Freezteq is an extremely cost-effective way of treating rising damp, particularly in comparison to the potential costs that may incur if left untreated.