Dampness in buildings occurs when materials absorb water, posing harm to the occupants. To address this issue, a Damp Proof Course (DPC) is implemented during construction, acting as a shield against damp entry.
1. Groundwater Table : When the groundwater table is high, the foundation materials absorb water through capillary action, impacting the building’s stability.
2. Rain :Unprotected external walls expose the building to rain, causing potential damage.
3. Poor Drainage : Buildings in poorly drained areas are susceptible to dampness.
4. Construction Quality : Bad workmanship during construction can lead to dampness issues.
5. New Constructions : Newly constructed walls may remain damp temporarily.
6. Roof Slope : A very flat roof slope may allow rainwater penetration, leading to temporary storage on the roof.
7. Wall Protection : Parapet and compound walls need damp proofing on exposed tops to prevent serious dampness issues.
Dampness can result in various adverse effects:
Several materials are used for damp proofing:
1. Use of Damp Proof Course : DPC materials, such as bituminous substances, stones, or cement, are strategically placed in the building to prevent water entry at vulnerable points like plinth levels and above concrete beds.
2. Surface Treatment : A thin film of water repellent material is applied to surfaces, filling material pores exposed to moisture.
3. Integral Damp Proofing Treatment : Water-repellent compounds are mixed into concrete or mortar during mixing, acting as barriers against moisture.
4. Cavity Wall or Hollow Wall : Cavities or air drains within walls prevent rising moisture from the ground.
5. Pressure Grouting or Cementation : Holes drilled at various points in the building are filled with a thin cement paste under pressure, ensuring a watertight structure.
By understanding dampness, its causes, effects, materials, and effective damp proofing methods, buildings can be safeguarded against potential harm.
