Walls Humidity:condensation, Mould Problems

January 19 2013

We live in a difficult world and for many of the problems that affect our planet the only responsible is the human race.   Today each one of us is asked to do something to try to repair (at least partly) the disaster that we have done in the past. We can start with small things like our home, saving on fuel that’s means contribute to save our planet and …our wallet!


To effectively combat the problems related to the umidity and mould on the walls of your home, it is necessary to first understand what the condensation is and where it is coming from, only then it will be possible to establish and set up a strategy to deal in order to avoid it.

The sensation of cold that we feel usually depends largely on the temperature, but also there is another factor that can make us uncomfortable: is the moisture of the walls, floors and ceilings that surround us.

This phenomenon is known as radiation and works exactly like the radiant heaters do, that means they heat only the air strip stright in front to them. In the same way when you stand in front of a fireplace you feel warm your front body while your b-side is cold.

Exactly the opposite if you stand in front of a window on a winter day.

The temperature that is felt is called ‘Operating Temperature‘, but to get the feeling of warmth also walls, ceilings and floors should not be cold. To have this it is necessary to create a barrier with insulating coatings.


The moisture is determined from the steam that is deposited on the surfaces. This is due to the heat shock that occurs only below 68° F (20° Celsius).

The air around us consists of various elements and between them a certain amount of steam that comes from the evaporation of water in the environment. The air soaks up the water vapor until it becomes saturated. The higher the temperature the more pronounced is the phenomenon.To give an idea of this, we must know that 35 cubic feet (1 cubic meter) of saturated air, at sea level and at 32° F contains 1/8 of an ounce of water at 32° F (0 ° Celsius), almost 1 tbsp at 50°F, almost 1 cup at 68° F. and almost 3.3 ounces at 122° F..

The Relative Humidity is the percentage of water present in the air (measured by the hygrometer)

If we cool the air the water vapor is expelled. If cooling process is made very fast, the steam turns into water giving rise to the Condensation drops that are deposited on the cold surface. In fact, the temperature at which condensation starts is called dew point. Pratically, the steam water remains in the air until its quantity is appropriate to the humidity level, when it exceeds the excess is deposited on the cooler surface in the form of drops.

When it rains, there is foggy or it’s snowing, the outside air humidity is high and usually higher than inside, then there is a good chance of condensation.

To this also contribute several other factors such as the presence of living people, animals or plants in addition to the production of steam from the normal daily activity, such as cooking food, use of toilets and showers, etc.

It is confirmed that each home usually produces more than 10 liters of water per day that are poured into the air.

In addition to the above, other factors also contribute to the formation of moisture and condensation as for example the modern construction techniques that greatly reduce the step of drying of walls, plaster, ceilings, floors and tiles. Add to this the insulating effect of the materials used that, if on the one hand are useful to prevent ingress of moisture and cold, the other does not allow an adequate exchange of air with the outside environment.

Drops of condensation on your windows are a signal that the problem exists and must be solved as soon as possible. A delay in finding the proper solution will result in risk to your health and possible money loss.


Clearly, if an environment result moistly it will be necessary find and reduce the source of moisture and not to over heating.

But there are two fundamental factors:

  1. create air circulation
  2. avoid or reduce the thermal shock

While the first point is not so hard to do, for the second it could be another story.

Let us make a statement: in practice it is mandatory to avoid that an inner surface comes to be in contact with an external environment with temperature lower than the dew point inside.


For example, for an environment with internal temperature of 68° F and humidity 50% , the dew point is located at +49.3° F so if the surface (for example a tile) maintains a temperature over the dew point, the danger of condensation is avoided.

It is possible to get this result by reducing the steam produced through installation of double glazing on your windows, outer coat, coating the inner walls with insulating materials like polystyrene, extruded, cork or similar, by creating a ventilated heating system.


1 Comment

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Mar 7, 2015 at 5:23 AM

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