Dampness in building may occur due to bad design, faulty construction and use of poor quality of materials. This dampness not only affects the life of the building but also creates unhygienic conditions of the important items of work in the construction of a building. The treatment given to prevent leakage of water from roof is generally termed as water proofing whereas the treatment given to keep the walls, floors and basement dry is termed as damp proofing.
The three primary causes of dampness in building are
- Poor quality of construction material
- Bad design
- Faulty construction or bad workmanship
1.Poor Quality of Construction Material
Most of the construction materials such as concrete, brick or plaster possess interconnected void within them. When these materials come in contact with water, water finds a path to penetrate into these voids. Again this water when aided by capillary action; moves in different direction causing dampness.
At the time of designing a building, it is very important to consider what can be the source of water that can penetrate through building and accordingly the designer must mention where to provide what kind of damp proof course.
3.Faulty Construction or Bad Workmanship
Suppose a designer has specified that the thickness of damp-proof-course must be 15 mm. but due to lack of adequate supervision, the thickness of completed damp proof course become 10 mm. then this will not serve the purpose for which it is constructed and consequently it will lead to dampness in building.
Defects Caused by Dampness in Building
The various defects caused by dampness to building may be summarized as under:
- Efflorescence which may ultimately result in disintegration of bricks, stones, tiles etc.
- Softening and crumbling of plaster.
- Bleaching and flaking of paint with the formation of coloured patches.
- Warping, buckling and rotting of timber.
- Corrosion of metals.
- Cause deterioration to electrical fittings.
- Promotes growth of termites.
- Creates unhealthy living conditions for the occupants.
Methods of Preventing Dampness in Buildings
- Membrane damp proofing
- Integral damp proofing
- Surface treatment
- Cavity wall construction