What exactly is capillary damp?

Capillary rising damp is characteristic of old buildings, built at a time when builders were unaware of waterproof materials such as bitumen and the like, which are now used for waterproofing. Moreover, old buildings are often built without foundations, directly on the ground.

Since the basic construction materials (brick, stone, mortar, concrete…) are to a greater or lesser extent porous, through them, that is through microcapillaries existing in their structure, damp gradually moves upward from the soil.

The “culprit” for this is the surface tension of water, which occurs due to the polarisation of water molecules, and its direct consequence is capillarity. Due to capillary action, water “climbs” up the wall, and while moving, creates an additional electromagnetic field in the wall, which enhances the capillary effect.

Given the structural and static characteristics of these facilities, in capillary rising damp sanation the appropriate method must be carefully chosen. Classical methods, that is, construction (physical) methods of sanation – “pressure injected systems” and “slot sawing”, are very aggressive to the static of the building. Therefore, when it comes to old buildings, such sanation methods are not recommended either by the civil engineering profession, or the institutions dealing with the protection of cultural and historical heritage.

Capillary damp may also occur in newer buildings, which were waterproofed during construction. With such buildings the problem lies in damaged or deteriorated waterproofing.

Moreover, in the case of floods, capillary damp often remains in the walls due to waterproofing crack bridging.

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