Damage from rising damp
Damage from groundwater or rising damp can be seen on wet walls and floors in the basement, and further on deposits on the foundation. In severe cases, the moisture reaches the outer wall several meters high and affects it from the inside.
Visible moisture spot often tip of the iceberg
The place where the moisture damage can be seen is often just the tip of the iceberg: if, for example, a cellar wall is very moist in one place, this means at the same time that a larger part, perhaps the entire wall, is soaked with water. The repair costs are correspondingly high, especially since you cannot carry out many necessary work yourself, but have to leave it to a professional company.
Many chemicals are offered, especially with regard to damp cellars: special sealing pastes or mortars prevent the moisture from penetrating the cellar walls. The products are applied to the walls and form a continuous insulation layer, through which no water can penetrate.
Anyone who uses a cellar as a living space or storage place is not only concerned about moisture problems in the building construction, but also about moisture damage to movable property. Here it makes sense to provide basement walls and / or the floor with an insulating layer on the inside, which stops moisture penetrating.
Insulation on the inside often not sufficient
However, if the cause of the moisture damage is a defective or damaged groundwater barrier, moisture-proof mortars and insulating layers on the inside are little more than symptom control and also dangerous. They provide the false assurance that the damage has been remedied by applying the insulating layer. The opposite is true: the water remains in the wall and thus permanently affects the building structure. Worse still: the water that can no longer escape into the basement, searches for new ways through the building construction, thus creating moist building elements that were previously always dry. For example, new moisture damage can occur in outer walls, because the water now rises in here.
Eliminate causes of rising damp
It is therefore very important to remove the cause, and not just to combat the symptoms, especially in the case of damage caused by rising moisture from the ground. Due to the versatility of the problem, it is hardly possible for the layman to expertly assess the moisture damage and determine the necessary repairs. Usually the professional has to be involved.
For example, while damp and wet basement walls may be due to inadequate or damaged insulation to reverse groundwater, the reason for the damage caused by moisture may not necessarily be there. The damage may be due to excessive condensation: warm air in the basement hits the walls, which are permanently cooled by contact with the damp earth: the moisture settles on the walls. This problem can be solved with the right heating and ventilation, and in this case an insulating layer on the inside of the walls is even useful, because it protects the construction against condensation and its consequences (mold).
Salt rash is an additional problem
If moisture from the ground penetrates into the walls, it will rise due to the capillary action of the wall until it can evaporate again, for example near the foundation or in an outside wall. The water also takes all kinds of substances with it, such as table salt, gypsum, lime or sulphates, chloride and nitrates. Such substances are deposited in places where the moisture evaporates again. After a longer period of time a rash (saltpetre) develops as an additional problem. Such substances seriously damage the walls, so much so that stone is completely eaten away.
Salts enhance the capillary effect
Salts attract moisture and absorb it. This activates the capillary effect even more, because the wall can absorb more moisture, which also spreads faster. In addition, the salts extract water vapor from the air, so that an additional moisture load is created. The extent to which the substances deposit on the wall depends on the soil conditions. In agricultural areas, for example, the soil load from nitrates is very high.
Incidentally, a new invention was presented some time ago by a German company in which a simple box on the wall can be used to combat rising damp without chemicals. Normally, rising moisture creeps up in walls and foundations and also transports various salts. The ?? German box ?? now, takes advantage of the excellent current-conducting properties of salt. An electromagnetic impulse provides the salt with a different charge, causing the moisture to make a reverse, downward movement. That box ensures that the water leaves the wall within a radius of twelve meters.
Treatment with nitre remover
If there is a salt rash, it is not enough to combat the saltpetre with special means. Rather, it comes down to eliminating the cause of this damage. Nitric remover is a liquid with which the masonry is soaked. This is easiest with a large brush. Depending on the degree of rash, the wall must be treated several times. Before and after the treatment, clean the wall with a wire brush so that the dissolved salt deposits are removed. Such products contain chemical agents – so you should always follow the manufacturer’s safety instructions and wear gloves when working.