Humidity, „ascending“wetness, mould, etc.

Problems, which are the worst case for each house builder and which can be very expensive. In the order how it is described in the title, they appear in many buildings and are the reason for some sorrow, construction damages and furnishing damages, as the consequence are high repairing costs/reconstruction costs and for the inhabitants significant health risks, reduced living comfort.

Where do the humidity, the wetness and the mould come from?

Here a selection of the most mentioned reasons:

1. Construction damages, construction faults
2. Thermal bridge
3. Bursts, false behaviour with water
4. Water entry from outside, hillside pressure
5. Weather, extreme weather conditions (rain, mugginess)
6. Shower, bath, washing, cooking
7. very strong inhabitation
8. Ascending humidity from the earth in the basement walls, bottom
9. Few and false airing

Declarations for this:

1)
False and bad executed construction work and/or the use of damaged construction material can be the cause for construction defects and as consequence the cause for construction damages. Leakiness is not only responsible for permanent energy loss and for raising heating costs but also for direct damages.

2)
Thermal bridges are the reason for added energy loss and for this to an arisen dew point danger at this place. A basement wall is not insulated, so this is a huge thermal bridge.

3)
Water pipe bursts or negligent behaviour is an anomaly.

4)
Confined groundwater due to flood water or hillside pressure is an anomaly and it is not necessary to consider this in a significant way.

5)
In the case of rain and summer mugginess, the air humidity is extremely high, heated screed can not be the dew-point.

6)
These are the common loads of a flat, which are often given in an overstated way.

7)
Usually 1, 5 l of transpiration per day and person is calculated. Humidity which is important particularly if there are living several people in one room.

8)
This subject often concerns the basement, but the most professionals think that it is humidity which comes into the wall from outside and which comes slowly later from below to the top due the hygroscopic effect in the construction material. But the damages comes rarely from the water which comes from outside, it is the consequence of false airing. If it would be water from outside, this would not come slowly, but like in the case of strong rain or flooding it would penetrate within some minutes through the porous defects in the brickwork.

As in a lot of cases the basement is sunk in loamy earth, a penetration is very implausible, because the water needs many years in order to sick in depths of 1 or 2 meters. In the case of loam sand it would be clearly faster, still faster in the case of humus and faster in the case of grit.

The real reason for wet basement walls is for more than 90 % the humidity in the air because of untimely false airing. A lot of people think that their basement is getting dry in the summer if there is nice weather. They open all windows and doors, in order to let warm but humidity air in the basement. Exactly this is wrong, the basement walls has mostly only between 10 and 14 degree due to the missing exterior insulation. The air cools down and the humidity falls below the dew-point and condensed at the surface of the walls. Due to the fine porosity of the plaster and the building bricks, the hygroscopic effect appears and the humidity enters deeply into the walls. Dependent of a specific water quantity different chemical processes begin into the construction material, salts come to nothing and arrive the surface, a lot of microbes begin to accrete, also mycelium which is the beginning of mould. Anytime you can see the difference between strongly affected and fewer affected damaged brickwork and the division rule arises slowly. It can be explained easily, because lower walls are a lot of cooler than the walls on the top, so there is more condensation and you can see the damage much earlier. It is an accumulating effect, which appears as “ascending wetness”. “This is not the little humidity in the air” this is the opinion of a lot of people. You bet! You have to calculate the water part of the air in the case of e. g. 30 degree in the case of assumed 50 % humidity (14g/kg) multiplied by the volume of the room of the basement (8x10x2, 2m³)multiplied by the spec. weight of the air (1,2 kg/ m³), multiplied by the change of air per hour (10 in the case of slight wind) and you have to consider the dew-point of the walls of approx. 12° (8g/kg), than you get the water quantity of (14-8)x176x1,2x10=12672 g, which means 13 l each hour and in 10 hours you obtain a full bath tub. Since our summers are coming to approx. 100 beautiful day (but not everyday has 30 degree), you have the possibility to store approx. 10000 l water in the basement. You see, there must not be flood water or leak water from outside.

9)
Uncontrolled airing with the window can never be the adapted answer to the weather and season regarding the necessary air change rates. Additionally it is a complete energy loss in the cold season. But if you air too little you have the risk to obtain mould.


If false airing augment humidity in the house and at the same time you pander the growth of mould, it is important to correct the faults by correct controlled airing.

Here is helping the golden airing rule::

You have to air if it is cooler outside as inside and you have to air less if it is vice versa.

In order to comprehend it easier, see the declaration regarding the humidity diagram (see information).


The often offered alternative reconstruction measures for humid walls, like the separation of walls with metal plates etc or chemical measures, electronically moss are not only very expensive, they are also ineffective or they help only temporary. You can read a comprehensive control report of an Austrian institute concerning the electronically moss, which summarized the result as follows: The effect can be controlled mathematically physically, but the effect is too slight, for this reason useless.
But the producers demonstrate success regarding this kind of products: The trick is: With the fitting of the apparatus, the user is advised “new” airing regulations. If he executes the “new” regulations, he will reach the desired success.

In order to obtain a guaranteed success, it is more effective to upgrade a controlled airing with WRG of GF-SOL-AIR!