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Sussex Damp Surveyors
Sussex Damp Surveyors specialise in surveys, we don’t carry out remedial works and therefore will provide you with an honest and impartial assessment.
Rising Damp
Rising damp is a prevalent concern in older structures, characterized by the upward movement of groundwater through walls, floors, and masonry via capillary action—a process akin to how oil ascends through a lamp's wick. The porous nature of bricks and mortar facilitates this movement, with water traversing numerous fine capillaries.
However, true rising damp is relatively uncommon. More frequently, building defects or adaptations lead to moisture issues that manifest similarly to rising damp, or condensation and salt contamination problems are mistaken for rising damp due to shared symptoms. Recognising these distinctions is crucial for accurately diagnosing and effectively addressing moisture-related concerns in buildings.
Condensation
Condensation stands as the predominant cause of dampness in buildings, responsible for the majority of reported damp issues. It impacts both old and modern properties, with a notable prevalence in renovated buildings. Three key factors contribute to condensation: Relative Humidity, Air Temperature, and Surface Wall Temperature. These factors collectively determine the Dew Point, the critical threshold at which condensation occurs.
Condensation is often mistaken for rising damp, particularly as it frequently affects the lower sections of internal walls, which tend to be cooler due to the natural rise of heat. However, a distinguishing feature of condensation is the presence of mould on surfaces. If mould is visible, it is likely a result of condensation rather than other forms of dampness. Understanding these nuances is essential for accurate identification and effective management of moisture-related issues in buildings.
Salt Contamination
Salt contamination, particularly prevalent in older chimney breasts, presents a frequent challenge. This contamination typically stems from the combustion of fossil fuels, such as coal, in the fireplace. As coal originates from the earth, it may contain salt minerals like nitrates, chlorides, and sulphates. When burned, these salts manifest in the brickwork. Over time, especially if the fireplace is no longer in use, these salts can migrate from the brickwork and accumulate in the wall plaster.
Subsequently, these salts become hygroscopic, meaning they can attract and retain atmospheric moisture. Consequently, damp patches associated with salt contamination often worsen during humid weather conditions. This process is also observed in areas with historical rising damp issues. When moisture rises from the ground, it carries the aforementioned salts with it. If rising damp is addressed without considering and addressing these salts, they may persist within the structure, continuing to absorb moisture from the atmosphere.
Penetrating Damp
Penetrating damp refers to the horizontal ingress of moisture through a building's wall fabric, a problem that can afflict any structure. Even if it doesn't penetrate all the way through a wall, penetrating damp can inflict damage by deteriorating brickwork or timbers within the structure before becoming apparent on the interior surfaces of a property.
This type of dampness is frequently attributed to issues with roofs, guttering, external wall finishes, or windows. If left unaddressed, penetrating damp has the potential to compromise the structural integrity of a property, particularly if supporting timbers are affected. Understanding the sources and implications of penetrating damp is crucial for safeguarding the structural health of buildings.
Timber Decay
Timber decay encompasses two primary categories: rot and beetle infestation. Rot further divides into dry rot and wet rot, also known as brown and white rot, respectively. Beetle infestation encompasses all wood-boring insects that feed on timber within a property, with woodworm (or common furniture beetle) being the most familiar.
In both rot and beetle infestation cases, except for a very small minority, high moisture content within the timber is the primary culprit. It's generally acknowledged that a moisture content of 20% or higher could precipitate timber decay in some form. Elevated moisture levels often stem from various issues, most commonly associated with roof leaks, inadequate ventilation, pipe leaks, or other forms of dampness.
