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Treatment of humidity, condensation and mold

Sanitize your home against condensation and humidity

Mold is a generic word for several fungi whose spores are present in the atmosphere. It often manifests itself in the form of green, brown or black spots on walls, leather objects, clothes, furniture …

These stains most often appear in the corners of rooms, unventilated bathrooms, around windows or where the walls and ceilings are not (or poorly) insulated, that is to say more cold (thermal bridges).

Mold is almost always linked to a problem with condensation, that is, the production of humidity not evacuated in the house.

Our teams can help you identify the source of any condensation problems. Once the diagnosis has been made, we offer you adapted solutions depending on the parts affected. In some cases, simple ventilation advice will suffice, in others we install a specific ventilation device.

Where ?

  • In damp rooms: bathroom, kitchen, laundry room, etc.
  • In the bedrooms
  • In poorly ventilated places: cellars, false ceilings, etc.
  • On poorly insulated walls or walls, at the level of thermal bridges


  • The phenomenon of condensation occurs as soon as too high a humidity level is released into the air in a room.
  • This problem becomes more pronounced in winter or during sudden changes in temperature.
  • Appearance of mist on windows, walls and floors during seasonal climatic changes.
  • Appearance of mold.

Why do it ?

  • Prevent degradation of paints or wallpapers
  • Improve living comfort by guaranteeing regular air renewal and oxygen supply in living rooms
  • Protect yourself from the harmful effects of mold on your health: the spores released into the air by molds can cause irritation, allergies in more vulnerable people such as seniors, children and people with weakened immune systems or in pain breathing problems.

TheProcessing steps of a treatment against condensation


Diagnosing the problem


Detection of thermal bridges

and insulation advice


Choice of ventilation unit

by favoring double-flow devices with heat recovery


Coring (drilling) of the wall from the inside

diameter suitable for the ventilation device


Or core drilling from the outside


Installation and commissioning of the selected device

FAQ – find out more


Condensation (of water) is the phenomenon of precipitation of a matter in the gaseous state (in this case water vapor) into a matter in the liquid state (drops of water). Condensation occurs when the air is saturated with water vapor. It usually occurs in cold areas, when humid, warm air comes into contact with a cold wall or any cold surface (metal, glazing, thermal bridge).
You can see this phenomenon when you take a shower and you see the cold mirror (or the window in the shower room) being covered with water droplets, or when a child plays to exhale air. directly on a cold window in order to then be able to draw a design in the mist that it produced.

Moisture diagnosis - symptoms

Observation of the most common symptoms allows a diagnosis to be made.
The signs that do not deceive are:
1. The development and proliferation of mold on certain areas of the walls (corners of rooms, bottom of walls, concrete lintels, window towers and behind furniture;
2. An excess of relative humidity which manifests itself in fog on the windows;
3. In cold weather, appearance of water droplets on walls, floors, window lintels, window sills;
4. A musty smell inside the house.
5. During sudden changes in temperature, small puddles of water appear on the tiles, in the corners of rooms, on the floors and cold walls of cellars.

The damage

The damage is mainly located at the bottom and in the corners of the walls (traces of white, black and / or green mold), on the window towers, on the back of furniture, on leather objects or on wood. . There is also the formation of water droplets and mist on cold walls and glass surfaces.
The wallpapers, Gyproc (or Placo) panels which are factorycovered with a layer of cardboard (cellulose-based material) are elements conducive to the development of fungi of all kinds and a fortiori of molds.

What is "mold"

In mycology, “mold” is a vernacular term for multicellular microorganisms, generally a variety of fungi from the order of fungi. There are endless species of mold. Their spores are present in the air, both outside and inside homes, awaiting the conditions for their development.


These symptoms should not be confused with the signs of a problem with porosity, capillarity or rising damp that would require drying of the walls by injections. Condensation is not related to the presence of moisture in the walls, nor is it “coming out of the wall”. Its origin is the saturation of the air with water vapor. This moisture in the form of vapor is produced by human activity inside the house. Human activities that produce humidity and sources of evaporation are numerous: cooking, showering, bathing, breathing, drying clothes … All these activities produce water vapor.
Above all, remember that a condensation problem does not make the wall wet in depth, only on the surface. There is therefore no need to further waterproof the house or the walls, what matters is to ventilate the house well.

And health ?

Musty odors, mold spores and excess relative humidity, the lack of oxygen in the air are sources of discomfort and are harmful in the long term to the health of the occupants. Breathing unhealthy air is not desirable for anyone. People with asthma or chronic bronchitis should make sure they breathe fresh, healthy air. To do this, its habitat must be ventilated regularly. Ten minutes of ventilation morning and night is not enough.
For our neurons to function properly, the brain needs sufficient oxygen supply. During winter many dwellings have an obvious deficiency in terms of air renewal. By cooking, heating and even breathing, we produce CO2. Without regular air renewal, our homes accumulate this toxic gas and we live in an atmosphere saturated with CO2 without even realizing it. This results in a lack of oxygen which has a negative effect on health: our alertness is reduced and our ability to concentrate is impaired.

Preliminary study

Before doing any work, in order to eradicate the complex problem of condensation, it is necessary to:
1. Determine the premises to be treated as a priority;
2. Calculate the volume of these premises;
3. Determine which building materials were used for their construction;
4. Consider the tolerable noise level in the room.
5. Check whether the premises have an exterior wall on which to place the local ventilation system that will suit the room in question.
6. Determine if the walls, roof have been insulated, and how effectively.
7. Check whether the windows are fitted with double glazing and any grilles.

Solutions to combat relative humidity, condensation and mold problems

It is clear that window ventilation has reached its efficiency limits. Opening windows for ten or even thirty minutes in the morning and evening is not enough to guarantee a healthy atmosphere inside a home. If some people continue to sleep with the window open, this variety of badass tends to disappear. During the day, leaving a window open also poses a security risk.
In the city, the noise and pollution generated by traffic leave few arguments in favor of a window ventilation solution. Not to mention that the windows and doors have become increasingly airtight.
To prevent the development of molds and the harmful effects of condensation, it is also evident that mechanical ventilation is the solution promoted by design offices, architects and health organizations.
Spot spraying with bleach or fungicides can kill mold, but this technique is not effective over time. In addition, toxic products are added in the house without promoting the renewal of the essential air, it is a stopgap.
We will hardly speak more about humidity absorbers, “D” systems which are expensive in salt refills and which are not an ideal solution for health since they do not allow any supply of fresh air.
The same goes for the electric dehumidifier which is an efficient device, but its power consumption and noise level cause problems for long term use. Like absorbers, electric dehumidifiers do not provide a solution in terms of renewing fresh air and extracting stale air. Their only job is to remove moisture from the air.
To combat condensation problems by ensuring a supply of fresh air, the solutions are the permanent and reasoned ventilation of the home in combination with the insulation of thermal bridges and cold walls.
A plethora of ventilation systems are available on the market. The technical advisor will advise you in establishing a choice, a configuration that will combine several devices. They will be selected based on the answers to the following questions:

  • What noise level will be emitted by the ventilation device;
  • How much fresh air should you bring in depending on the volume and use of the room?
  • How much stale air should I extract?
  • In which case is it preferable to install a single flow Mechanical Ventilation? Should it be centralized (VMC) or local?
  • In which case should you install Double-flow Mechanical Ventilation? Should it be centralized or local?
  • What type of extractor to install in a bathroom?
  • What type of extractor will be suitable for a toilet?
  • What ventilation grilles should be placed on the front or in the windows?

A complementary solution to fight against humidity by condensation is to insulate all the cold walls of the home. This work does not dispense with the need for mechanical ventilation, on the contrary! Since the housing is more airtight, it will require even more ventilation.