Guide to moisture in the house

The main causes include rising damp, condensation, as well as defects in an installation.

Moisture effects in walls mostly overlap. Therefore, it is difficult to distinguish between two or more moisture sources acting simultaneously. However, in order to assess moisture-related damage, the sources must be identified. This is often done by an exclusion procedure in several steps.

These components can cause moisture if installed incorrectly:

• External facilities for rainwater (water barrel, cistern, gutter, downpipe, flat roof).
• Condition of bricks, stones, mortar, masonry bases, plaster, weatherproof coatings
• masonry construction, cracks in masonry, covers
• Structures adjacent to walls that lead water to the masonry, including leaking windows and doors
• Ventilations; their location and condition
• Chimneys and deflectors to protect against rain
• Any existing mechanical or chemical barrier layers against moisture
  
  

Can you rule out faulty installation and condensation as the source of the moisture? Then you can assume that you have capillary rising damp. Not sure? Then contact our experienced experts.

For water to rise through masonry units, it must pass through the capillaries or joints.

If a house is built of impermeable masonry blocks, moisture can still rise through the joints. Besides the capillaries, the joints are therefore the main routes by which the moisture, coming from the ground, rises in the wall of the building.

The installation of a system for electrophysical drying of buildings eliminates the water in the wall. As a result, moisture no longer rises to the top. In addition, the moisture contained in the building wall can continue to evaporate unhindered on the inner surface of the wall. The wall thus becomes dry.

How high moisture can rise in building walls depends on various factors. Rise heights above 1.5 meters are rather rare.

Important criteria include the size of the pores in the wall, the condition of the joints, the type of wall covering (plaster or paint) and the degree of moisture in the adjacent soil. In most cases, the moisture does not rise higher than 1.5 m. However, in extreme cases (e.g. where the wall has been covered with an impermeable layer), it can rise 2.5 m or more.

The installation of a system for electrophysical building drying reduces the suction tension in the wall. Moisture no longer rises to the top and the moisture contained in the building wall can evaporate. The wall becomes really dry.

Moisture in walls leads to the long-term decomposition of the building fabric. Physical, chemical and / or biological processes are responsible for this.

Physical process
In the case of building walls in and on which temperature changes occur, capillary moisture penetration promotes damage. For example, freezing of the wall surface encourages the top layer to flake off. In addition, the salts carried along with the rising water lead to an increase in volume. This increases the internal pressure of the wall. This can cause the wall to burst open from the inside.

Chemical process
If the building wall is made of reinforced concrete, the salts introduced by the rising damp attack the steel reinforcement. The chemical conversion of the iron in the steel to rust leads to an increase in the volume of the iron. The rust that forms in the concrete requires more space. This increases the internal pressure in the concrete. This increased internal pressure encourages the top layer of concrete to flake off.

Biological process
Enforcement of the building wall with harmful fungi can lead to uncontrollable reactions in the building material used and to its slow destruction.

The installation of an electrophysical building drying system eliminates the water in the wall. As a result, moisture no longer rises to the top. In addition, the moisture contained in the building wall can continue to evaporate unhindered on the inner surface of the wall. The wall thus becomes dry. As the wall dries, the basis for decomposition processes is removed.

Saltpetre efflorescence, also known as masonry saltpetre, consists of calcium nitrate. They are formed when lime is dissolved out of the mortar or concrete and converted into calcium nitrate. With alternating moisture penetration and subsequent drying, the lime dissolves and crystallizes again. This forms the saltpetre efflorescence that is easily visible to the eye.

In the long term, this process can cause the masonry mortar, stone or concrete to weather and become brittle. This can destabilize your masonry. Do you have saltpetre efflorescence? Then you have a sure sign that your wall is at least temporarily too damp. Get in touch with our experienced experts.

Moisture caused by condensation is often due to incorrect ventilation. Basically, when ventilating, it should be noted that warm air stores more moisture than cold air.

If you ventilate your damp cellar for long periods in the warm season, you will bring more moisture into the room. This is because the warmer the air is, the more water it can absorb. In the summer months, warm, humid air usually enters the cellar. This air cools down in the cooler room. The humidity condenses on the cold surfaces. The water then condenses on the walls and other surfaces, as the cooling air can no longer retain the moisture.

Ventilation in summer therefore only makes sense if the outside air supplied is cooler or drier than the indoor air. Therefore, during hot spells, you should only ventilate in the cool morning hours or during the night. If you have an automatic system for ventilating your cellar, you should close or switch it off on hot days.

The situation is different if you have installed an intelligent ventilation system. Intelligent ventilation systems regularly measure the humidity and air temperature inside and outside the room. The device is programmed so that the cellar room is only ventilated via a fan if this prevents the humidity in the room from rising any further.

Do you notice damp in your rooms? But are you unable to be on site regularly to ventilate? Then an automated, intelligent, self-regulating ventilation system would be advisable. This system ventilates for you automatically and correctly. You are welcome to contact our experienced experts. They will present you with an intelligent ventilation solution adapted to your personal circumstances.

Depending on the type and use of the basement, you should leave, adjust or radically change your ventilation behavior.

Living room basement
Do you live in a new building with a well-insulated basement, or has the basement even been converted into living space? Then you should base your ventilation behavior on the values for living rooms. The optimum air humidity is then between 40 and 60 percent. It is best to ventilate the heated basement in the same way as your living rooms.

Storage cellar
If you have stored food in the basement, you will not heat the basement during the winter months. Then make sure that the temperatures do not fall below 0 degrees. Keep the windows tilted during the day. In the summer, keep the basement windows closed. Daily airing is not necessary for food storage. If you provide air exchange now and then in the early morning hours (between 5 and 6 o'clock), this is perfectly sufficient.

Wine / vaulted cellar
The vaulted cellar, which is slightly damp all year round, is also ventilated sparingly. To prevent a musty smell, open the cellar windows in summer early in the morning between 5 and 6 a.m. for approx. 30 minutes. In winter, you can leave the cellar windows in the tilt position during the day. You should only close the windows when the outside temperature is below zero.

Are you unable to be on site to ventilate regularly? Then we recommend installing an automated, intelligent, self-regulating ventilation system. This will automatically ventilate correctly for you. Please contact our experienced experts. They will design an intelligent ventilation system for you that is adapted to your personal circumstances.

⇓ Factsheet How to ventilate basement

The exact cost can be determined by one of our construction experts.

For the repair of more severe damage, we recommend an initial estimate of EUR 1,500 per linear meter of wall length. If waterproofing is required, we estimate an initial cost of EUR 350 per m². In some cases it may cost considerably more. External waterproofing in particular is expensive due to the earthworks required. We would estimate excavation work at 1,000 to 1,500 EUR per meter of cellar wall length.

For an electrophysical drying solution, we estimate around EUR 15,000 to 20,000 for a detached house with a floor area of 60 m². Simple dehumidification with a building dryer will cost you around EUR 50-100 for the rental and around EUR 100 in electricity costs.

The cause of the dampness should be fundamentally determined by one of our building experts.

The question arises as to whether the cellar walls are sealed from the outside. If water penetrates the cellar from the outside through cracks, for example, it will always get wet in your cellar. You can only speed up the drying process with drainage equipment, but you cannot prevent soaking.

Renovations and waterproofing can entail high costs. In some cases, they can cost as much as building a new basement. However, if you do not carry out the renovation, you risk damaging the building fabric that supports your house in the long term.

Rising damp in the wall can be controlled by subsequently installing a moisture barrier layer. Nevertheless, decomposition processes may occur.

The building wall or any infested façades can remain damp due to the salts they contain. This is because the water stored in the wall and the salts dissolved in it can no longer drain downwards through the installed barrier layer.

This can be remedied by installing an electrophysical wall drying system. Such a system ensures that moisture no longer rises upwards and that the moisture contained in the building wall flows downwards. This makes the wall dry.