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Damp proofing and defects due to moisture

Short answer

Damp proofing uses impervious layers like DPC, integral compounds, surface treatments, cavity walls, and drainage to stop moisture. Defects from moisture are stains, efflorescence, disintegration of masonry, timber decay, corrosion of steel, mould growth, reduced strength, damage to floors and furniture, electrical short circuits, and cracks.

What do you understand by Damp proofing in building? Illustrate the defects in building due to moisture.

Damp proofing is the treatment of a building, by providing an impervious layer (DPC) or other measures, to prevent moisture from the ground, rain or other sources from entering the walls, floors and roofs.

Methods in brief: membrane DPC (bitumen felt, polythene, cement concrete 1:2:4 with waterproofing compound at plinth level), integral waterproofing compounds, surface treatments (waterproof plaster and paint), cavity walls, guard drains, and grouting or injection in old buildings.

Defects in buildings due to moisture (dampness)

  1. Stains and patches on walls and ceilings; peeling or blistering of paint, plaster and wallpaper.
  2. Efflorescence: White crystals of salts brought to the surface, spoiling the appearance and breaking plaster.
  3. Disintegration of bricks, stone and mortar; softening of plaster.
  4. Decay and rot of timber (doors, windows, floors) and termite attack.
  5. Corrosion of steel and reinforcement, causing concrete to crack and spall.
  6. Growth of fungus, moss and mould, giving a bad smell and unhealthy conditions.
  7. Reduced strength and thermal insulation of walls.
  8. Damage to floor coverings and furniture; warping of timber floors.
  9. Electrical short circuits.
  10. Cracks and uplift of flooring due to swelling.
  11. Lower property value and uncomfortable living.

✓ Answer checked by Claude Opus 5.5 (high effort)

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