In this Article Learn

Causes dampness, Effects of dampness, sources of dampness : Rising moisture of the ground,From the external walls,  Top of walls, Condensation, prevention of dampness


One of the most important requirements .of a building is that it should remain dry, that is, damp proof. If this condition is not satisfied, it is likely that the building may become unhygienic to the inhabitants and unsafe from the structural point of view, because dampness breeds germs of certain diseases and disintegrates the structure.

Effects of dampness

The following are the effects of dampness :

  1. A damp building creates unhealthy conditions for the inhabitants.
  2. It disintegrates the structure.
  3. Unsightly patches, called efflorescence are formed on the surface of walls.
  4. Decay of timber takes place rapidly in the damp climate.

Sources of Dampness

The various causes which are responsible for causing dampness in a building are as follows :

Rising of moisture from the ground.

The subsoil moisture, present below the ground level, rises through the foundation beds due to capillary action.

From the external walls.

If the faces of walls are subject to heavy showers of rain, or if they are not being protected properly, the water will percolate in and causes dampness.

Top of walls.

Parapet and compound walls also become a source of dampness as the rain water descends down the wall and causes dampness.


When warm humid air is cooled, conden­sation takes place. Due to condensation, moisture is deposited on the walls, floors and ceilings and causes dampness.

 Prevention of Dampness

The following are the remedies for making a building damp-proof :

  1. By providing a layer of damp-proofing material between the foundation and the plinth, to check the rising of mois­ture from the sub-soil.
  2. By plastering the external walls which are subjected to showers of rain by cement mortar, so that rain water may not percolate in.
  3. By providing copings on the top of walls and parapets. This will prevent descending of moisture from the top of the walls.
  4. The building should be properly oriented so that, each room should have sufficient ventilation and may get sufficient sunshine.

(Orientation means, placing or arranging the various apartment of a building in such a way that each room or apartment gets the maximum benefit of natural light, air and sun.)