Dampness in Buildings
Damp prevention is a chief requirement to ensure safety of building against dampness. One of the basic requirements in all the buildings is that structure should be dry as far as possible. If this is not satisfied it is likely that building may become inhabitable and unsafe from structural point of view. In order to prevent entry of damp into a building the courses known as damp proofing courses are provided at various levels of entry of damp into a building. Presently all buildings are given DPC treatment So DPC prevent entry of moisture from walls floors and basements of a buildings The treatment given to roofs of buildings for some cause is called water proofing.
Cause of Dampness
Responsible causes are one or more of the followings
- Faulty design of structure
- Faulty construction / poor workmanship
- Use of poor quality of material in construction
These causes give rise to an easy access to moisture to the building from different points, such as rain penetration through walls, roofs and floors etc. The moisture entering into the buildings from foundation and roofs travels in different directions further under the effect of capillary action and gravity respectively. The entry of water and its movement in different parts of the buildings are positively due to one or more of the causes listed above.
- Rising of Moisture from the ground
The subsoil or ground on which the building is constructed may be made of soils which easily give an access to water to create dampness in building. Generally the foundation dampness is caused when the building structures are constructed on low lying water logged areas where a sub soil of clay or peat is commonly found through which dampness will easily rise under capillary action unless properly treated. This dampness further finds its way to the floors, walls etc. through the plinth.
- Action of Rain Water
Whenever the faces of walls are not suitably protected from the exposer to heavy shower of rains, they become the sources of dampness in a structure. Similarly the poor mortar joints in walls and cracked roofs also allow dampness to enter the building structure. Sometimes due to faulty eave courses and eave gutters, the rain water may percolate through the roof coverings
- Rain Penetration from top of the wall
All parapet walls and compound walls of the buildings which have not been protected from rain penetration by using dam proof courses or by such measures on their exposed tops are subjected to dampness. This dampness in the buildings is of serious nature and may results in unhealthy living condition or even in structurally unsafe conditions.
- Codensation Due to Atmospheric Moisture
Whenever the warm air in the atmosphere is cooled it gives rise to process of condensation. On account of condensation the moisture is deposited on the whole area of walls, floors, and ceilings. However the sources of dampness is prevalent only in certain places in India, where very cold climate exist.
- Miscellaneous Sources or causes
The various other sources responsible for dampness in buildings are mentioned bellow:-
- Poor Drainage of Site
The structure if located on low lying site causes water logged conditions where impervious soil is present underneath the foundation. So such structures which are not well drained cause dampness in buildings through the foundations.
- Imperfect Orientation
Whenever the orientation of the buildings is not proper or geographical conditions are such that the walls of buildings get less of direct sunrays and more of heavy showers of rains, then such walls become prone to dampness.
- Constructional Dampness
If more water has been introduced during construction or due to poor workmanship, the walls are observed to remain in damp condition for sufficient time.
- Dampness due to Defective Construction
Dampness in buildings is also caused due to poor workmanship or methods of construction viz inadequate roof slopes, defective rain water pipe connection, defective joints in roofs in proper connection of walls etc.
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