Moisture damages

To thermally insulated steep-pitched roofs and exterior walls

Many building shells have deficiencies! They concern not only the thermal insulation, but often also the vapour check, vapour seal or airtight layer.

Fortunately, these deficiencies do not always lead to construction damage, but often show up simply as compromising residential use or comfort (heat loss, draughts, etc.). All too often, however, they are the cause of construction damage, with far-reaching consequences.


Moisture from the outside

A non-airtight outer covering inevitably leads to damage due to moisture in the thermal insulation and the supporting structure. This is common knowledge today, and so maximum attention is paid to protection against weather effects.

Moisture from the inside

But how does damage occur due to moisture in thermally insulated steep-pitched roofs despite the hydrophobic weather-protection skin? Why does the whole construction become so wet that water drips into the building? This can be solely and exclusively the phenomena of water vapour condensation and air humidity.

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Such damage can be primarily attributed to lack of planning and poor execution of work or management of the building construction. Quite often the reason also lies in incorrect construction or choice of materials, but material defects are virtually never to blame.


The main reasons for damage due to moisture from the inside

Diffusion of vapour

If multi-layered, thermally insulated constructions are built incorrectly in terms of the order of their layers, large surface diffusion condensation may occur. Ventilation systems that are not fit for purpose can often be partially to blame. Caution is required especially in the renovation of old buildings!


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As a result of our modern demands in terms of living comfort and cosiness, we create a warm, relatively humid climate inside our buildings. Leaks in the building shell allow moisture to penetrate in a concentrated manner into the construction and can lead to a severe localised moisture build-up.


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Wind tightness

It is not uncommon for cold outside air to penetrate into the inner lining of a building due to a deficient building shell. Due to the cooling-off of the inner lining, surface condensation forms, which can result in discolouration or even mould formation.


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The damage patterns in moisture-loaded external walls and roofs are varied and often seem to be a big mystery even to the expert. For more exact study of causes, we can conclude that in addition to the obvious leakage to the outside, moisture from within the building very often leads to problems. In addition to unhelpful behaviours of property users, the following four main reasons can be mentioned: