Dampness of Wall | Damp Proofing Course

What is the Dampness of the Wall 

Dampness is the presence of moisture. It is the building may occur due to bad design, faulty construction, and the use of weak quality materials. It creates unhygienic conditions of living.

Causes and sources of dampness

  1. It is rising through the foundation wall due to capillary action.
  2. Splashing rainwater hitting the wall surface.
  3. Penetration of rainwater protects the top of walls in the structural element.
  4. In the case of a sloped roof, rainwater may percolate through the defective roof covering.
  5. On condensation, the moisture present in the atmosphere gets deposited on the component of the wall which causes dampness.
  6. Improperly constructed roof slaps, improper rainwater pipe connection
  7. Dampness may be due to leakage of pipe fitting of bathrooms, kitchen.


Effects of dampness

followings are the effect of dampness, it may.

  1. Resulting in rotting and crumbling of plaster.
  2. Cause flaking of paints and bleaching with the formation of color patches.
  3. Resulting in the warping buckling and rotting of timber.
  4. Lead to the corrosion of metals.
  5. Deteriorate electrical fitting
  6. It promotes the growth of termites.
  7. Creates unhygienic conditions for living.


Method of damp proofing

  1. Membrane damp provides a layer or membrane of water repellent material between the source of dampness and the part of the structure adjacent to it.
  2. It consists of materials like bituminous felts, cement, concrete, polythene sheets, etc.
  3. General principles to be observed are.
  4. The D.P.C. should Cover the full thickness of walls.
  5. When horizontal DPC is continued on the vertical face a cement concrete-filled 75 mm radius is provided.


Integral damp proofing

This consists of adding certain waterproofing compounds with the concrete mix to increase impermeability. Such compounds are available in marker in liquid or powder form. In general, one kg of waterproofing compound is added to one bag of cement.


Surface treatment for damp ness of Wall 

Moisture finds its way through the pores of material used in finishing. The walls plaster with cement lime and sand mixed in the proportion of 1:1:6 is found to serve the purpose of preventing dampness in the hall due to rain effectively.



Hunting of Dam pness of Wall 

This consists of depositing an imperious layer of rich cement mortar over the surface to waterproof the operation carried with the use of a cement gun.
The surface is to be treated thoroughly cleaned and wanted properly. Cement sand in proportion of 1:S is fed in the machine and this mixture is finally shot on the prepared surface under a pressure of 2 to 3 kg/cm^3.


Cavity wall construction for Dam pness of Wall 

This consists of shielding the main wall of the building with an outer skin wall leaving a cavity in between the two.


Idel requirement of material used for DPC

Ideal damp proofing materials should have the following characteristics

  1. The materials should be perfectly imperious.
  2. The material should be durable.
  3. The material should be strong and capable of resisting supper imposed load on it.
  4. Should be flexible so that it can accommodate the structural movement without any friction.
  5. The material should be economical.


The materials used for DPC are:

Hot bitumen
Plastic sheets
Cement concrete
Stones such as granites, states, etc.
Metal sheets.

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