Rising damp occurs when groundwater is absorbed into the walls or floors of a building. The water rises through the pores and capillaries in the building material, carrying with it soluble salts and minerals. As the water evaporates from the surface of the walls, these salts and minerals are left behind, leading to the formation of damp patches or stains. Over time, if left untreated, rising damp can cause serious damage to a building’s structure and can also lead to the growth of mould and fungi, which can be hazardous to health.
The most common cause of rising damp is a failure of the damp proof course (DPC). A DPC is a barrier that is inserted into the walls of a building at ground level, which is designed to prevent moisture from rising up into the walls. If the DPC fails, then moisture can rise through the walls, causing rising damp. Other causes can include a lack of ventilation, a high water table, or the use of porous building materials.
The signs of rising damp can be easy to spot, particularly in older properties. The most obvious sign is the appearance of damp patches or stains on the walls, particularly at ground level. These patches may be discoloured or may have a musty smell. Other signs can include peeling wallpaper, blistering paintwork, or the appearance of white, powdery deposits on the walls. If left untreated, rising damp can also cause damage to skirting boards, floorboards, and other wooden fixtures.
Treatment can be a complex process, and it is important to seek professional advice if you suspect that your home is affected by rising damp. The first step in treating rising damp is to identify the cause of the problem. This may involve carrying out a survey of the building, including an assessment of the condition of the damp proof course and any other potential sources of moisture ingress.
If the cause of the rising damp is a failure of the damp proof course, then the most common treatment is to insert a new DPC into the walls. This may involve removing a section of the affected wall and inserting a new barrier, or injecting a chemical damp proof course into the walls. Other treatments can include the installation of ventilation systems to improve air circulation, the use of waterproof coatings on walls or floors, or the installation of a sump and pump system to remove excess water from the building.
Preventing rising damp from occurring in the first place can be the most effective solution. This can include regular maintenance of the building, including the repair or replacement of any damaged or defective building materials. Ensuring that the building has adequate ventilation and that the ground outside the building slopes away from the walls can also help to prevent rising damp.
In conclusion, rising damp is a common problem that can occur in any building, particularly older properties. It is caused by a failure of the damp proof course, a lack of ventilation, or the use of porous building materials. The signs can include damp patches or stains on the walls, peeling wallpaper, or blistering paintwork. Treatment can be a complex process, and it is important to seek professional advice. The most common treatment is the insertion of a new damp proof course, although other treatments may be necessary depending on the cause of the problem.