- 2076 Baisakh · 6 marks
Damp-proofing versus water-proofing
Short answer
Damp-proofing prevents moisture ingress from capillary water and vapour, typically using a thin bitumen felt or concrete DPC at plinth level, and cannot resist hydrostatic pressure. Waterproofing is designed to hold back water under pressure, employing thicker, multi-layer membranes like APP/SBS or PVC on roofs, basements and tanks.
Differentiate between Damp-proofing and Water-proofing.
| Point | Damp-proofing | Water-proofing |
|---|---|---|
| Meaning | Prevents moisture and vapour from entering or rising | Prevents the entry of water, even under pressure |
| Water condition | Low moisture, capillary water, vapour | Water standing or under pressure |
| Used for | Walls, floors above ground, plinth | Roofs, basements, tanks, swimming pools, bathrooms, terraces |
| Pressure resisted | No hydrostatic pressure | Resists hydrostatic pressure |
| Materials | DPC: bitumen felt, cement concrete with compound, polythene, slate | Membranes (APP/SBS, PVC, HDPE), mastic asphalt, crystalline coating, epoxy, polyurethane |
| Layer thickness | Usually a single thin layer (a few mm of felt or polythene, or about 40 mm of concrete DPC) | Thicker, often a multilayer system |
| Cost | Low | High |
| Place of application | Usually at plinth level in walls | Over the whole surface (roof, basement) |
| Example | DPC at 150 mm above ground | Roof waterproofing with brick-bat coba and membrane |
✓ Answer checked by Claude Opus 5.5 (high effort)
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