One of the key areas of concern in building construction is how to tackle dampness. Dampness not only causes extensive damage to the building materials but also deteriorates the living conditions in the affected space. Hence it is essential to take the necessary precautions during the construction stage of the building so that problems related to dampness are prevented. Let us first look at the different ways in which dampness can affect buildings and how damp proofing can help:
Effects of Dampness
- Dampness leads to efflorescence due to which the unbound salts in materials like brick, mortar are brought to the surface forming an unwanted deposit on the surface. This harms the aesthetics of the building.
- Water contains chlorides which damages concrete and thus renders the building structurally weak.
- Dampness is particularly damaging to the reinforcement used in the structure. Dampness may lead to corrosion of the reinforcement bars causing irreparable damage to the strength of the building.
- Paint starts flaking in presence of dampness giving the surface a disfigured look.
- POP or plaster of Paris finish swell in presence of dampness.
- Dampness is also detrimental to timber. Wood furniture and wooden building members can be damaged beyond repair if they come in contact with dampness.
- Dampness leads to growth of fungi and termites making the space uninhabitable.
Due to the above ill effects of dampness, it is imperative to use damp proofing materials during construction.
Damp Proofing Floor
The major source of dampness is the earth. Moisture rises from the ground and seeps into the walls and floors through capillary action. This can be prevented by providing a damp proof course at the plinth level of the building. Various damp proofing materials can serve as a damp proof course. Continuous plastic sheets are frequently laid at the plinth level to combat dampness. Bituminous membrane and mastic asphalt can also be used for this purpose.
An excellent way to prevent dampness is by adding water proofing compounds to the mortar or concrete mix during construction. Example of one such damp proofing material is impermo by Snowcem paints. Adding 1 kg or 200ml of impermo to every 50 kg of cement renders the resultant concrete impervious to dampness.
Damp Proofing Wall
Dampness may also be caused by rainwater splashing on the walls of buildings. Cement plaster and waterproof paints are effective in handling dampness caused by rains.
Damp Proofing Roof
The roof is another source of dampness. The roof should not allow rainwater to stagnate on it. Thus it should be ensured that proper slope and drainage is provided in the roof. The drainage should be periodically checked for any clogging. The roof can also be treated with a layer of bitumen felt to prevent water seepage.