How to resolve dampness in walls | Part 1

Similar to illnesses and other problems in life; it is better to prevent than to cure. I meant by "better" that it will be more economic and it will produce fewer aggravations.


Early detection of stains of moisture is crucial to reduce the costs of treatment and to resolve the problem of dampness.


Even if often painted, well maintained and good care has been taken of the property; old houses sooner or later will have humidity showing somewhere. That is the eternal enemy of households. It is like a frightening monster that appears behind beds, on the ceiling or the bathroom. Walls look raggedy, lose colour and soon the entire house acquires a sense of darkness and abandonment.

The control of humidity in homes is a complicated task because it appears little by little. When for some reason concentration in specific areas appears most people tend to fix only the affected part of the wall or floor instead of solving the problem throughout the property if it is a reoccurring problem, which is understandable, especially if one considers that the rate to be paid for a builder could be around 35 Euros per hour. Reforms in general, masonry and tiling are also charged per square meter of area and could reach up to 40 Euros.

But the humidity not only causes dreadful aesthetic effect, its consequences are more serious because it can cause fungi and microorganisms that can be harmful to health, especially for people who suffer from allergies. For this reason, it is very important to treat the affected wall, ceiling etc as soon as dampness pokes out.

Prevention is better than cure.

Moisture, in the long run, may damage beams and slabs, destroy partition walls, distorts wooden doors and oxidizes metal frames and cabinets. The causes of their appearance are multiple, but the most common are leaks. However, it can also appear in closed environments where there are large condensation nearby such as bathrooms or kitchen, and result in the creation of fungi that can attack shower curtains, wood furniture and cabinets.

I strongly recommended finding out where the source of the leak comes from and proceed to repair it as soon as possible. I cannot emphasize this strong enough. Any delay or any other solution trying to hiding the damp or masking it off is a waste of time. Proceeding to treat the damp without knowing its origin involves a vain expenditure of energy, time and money, since sooner or later humidity will reappear.

One of the most common reasons why there are moisture and fungus on walls are the concentration of water moisture in the environment, specifically in areas such as kitchen and bathrooms. But its expansion can be prevented with good ventilation. The obvious solution will be opening windows for at least half an hour each day, to prevent condensation or retention of moisture in the different rooms. Some building materials are more sensitive to the increase of moisture in the environment, such as plaster board or timber, which increase its volume and, even, cause cracks and fissures in walls and partitions.

Types of dampness.

  • Dampness by capillary action: appear in areas that are in direct contact with the ground as in ground floors or basements, since water passes by capillary action to any porous construction materials such as plaster, concrete, mortar, wood, ceramics, etc. Characterized by horizontal dark lines its origin is found in a poor waterproofing of the building. Lack of damp proof courses or water filtration from nearby wells etc.
  • Humidity from water pipes leakage due to pipe cracks or breakage: produced by a failure in pipes that are inside walls, i.e. pipes embedded in walls or floors. Except in very specific cases, these leaks tend to loos out water slowly but constantly. Its spread can be uneven, making it difficult and cumbersome to find its origin.
  • Environmental humidity: depend on the environmental situation of the building. Is not the same a house on a beach front, with aggressive and constant humidity on the materials than another one situates in a dry area with more or less constant temperature. Marine environments are considered aggressive by the high humidity and the salt content that it carries.

Tips and advice

  • Aerate all zones within the dwelling so there is a constant stream of air.
  • Place doors with a double air intake to facilitate air movement or install an electric dehumidifier to absorb moisture.
  • Thermal insulate external walls and paint internally with a special anti fungi paint.

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