What is capillary rising damp (capillary damp)?
Capillary rising damp is a common problem. It most often affects the walls of buildings. This occurs when moisture from the ground or other source travels up through the walls by capillary action. Capillaries are fine channels with a very small diameter, which in most cases are connected to each other and, together with the air, form a network that passes through the building material. Water moves as a result of the great molecular attraction between the walls of the capillaries and the liquid through the channels and climbs up them contrary to the laws of gravity. The action of capillarity causes water from the ground to be absorbed upwards through the pores or capillaries in the walls.
Signs of rising damp inside the premises
Moisture rising by capillary action on interior walls can lead to efflorescence, peeling or peeling of wallpaper, and mold formation on interior walls. This not only disturbs the aesthetic appearance of the premises, but can also cause serious health problems.
Damp in walls can be caused by a variety of sources. That's why it's important to find out exactly where the moisture is coming from to save time and money on improper treatment.
Capillary rising damp is most often identified by visible wet spots on the plaster or as flaking paint on the wall. In most cases, these spots reach a meter, a meter and a half above the floor skirting.
This is the point at which the capillaries in the brick stop moving moisture upward due to gravity and natural evaporation.
Signs of rising damp in exterior walls
Moisture build-up on exterior walls can cause building damage such as plaster deterioration, efflorescence and masonry cracks. When looking for evidence of capillary damp on exterior walls, you should again look for specific stains. You may also see salts on the surface, compromise of the mortar between the bricks or stonework, and wetting and falling of the plaster.
How to deal with capillary moisture?
First, a detailed survey and analysis of the possible source of moisture and the condition of the structure must be done. Once identified, the best method for stopping capillary moisture is a two-part process.
1. Stopping capillary damp at source
In every newly built structure, a physical barrier is placed to cut off capillary moisture, in the form of a membrane. This includes removing at least the first course of bricks, removing the mortar and installing a physical waterproofing membrane. However, installing a new barrier of this type in an existing structure is prohibitively expensive and impractical in most situations. Therefore, an alternative solution is required.
The most practical and cost-effective method is to use a creamy, super-hydrophobic, non-toxic emulsion. Before its application, the plaster and other wall coverings are removed. The product is injected through holes drilled in the wall, as a result it liquefies and enters the capillaries of the material from which the masonry is built. After curing, it becomes a breathable and water-repellent chemical barrier that stops capillary moisture.
Done the right way, this solution is extremely long-lasting and effective.
2. Restoration of plaster damaged by hygroscopic salts
Although the chemical barrier has an almost immediate effect, hygroscopic salts may still be present in the wall. After injection with the emulsion mentioned above, we recommend to lay a new, certified plaster based on NHL natural hydraulic lime, according to BDS EN 459, which is ecological, suitable for anti-moisture, anti-salt, anti-condensation treatment of any type of water-saturated walls, outside and inside .