---
title: "Damp-proofing versus water-proofing"
subject: "Building Technology"
chapter: 1
key: "semester_6/building_technology:damp-vs-waterproofing"
source: https://www.bctengineer.com/q/semester_6/building_technology/damp-vs-waterproofing
site: BCT Engineering
---

# Damp-proofing versus water-proofing

Building Technology · Chapter 1: Functional Requirements of Buildings

- Asked in: 2076 Baisakh, 6 marks
- Video: [Dampproofing vs Waterproofing](https://www.youtube.com/watch?v=3c1Vi5wLi5U) — Fiebig Architecture
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/damp-vs-waterproofing
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-1

## Question

Differentiate between Damp-proofing and 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.

## Answer

| 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 |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which resists hydrostatic pressure?
   A. Damp-proofing
   B. Both do equally
   C. Water-proofing
   D. Neither does
   Answer: C. Waterproofing stops water even under pressure; damp-proofing does not resist hydrostatic pressure. (Key point: Pressure)

2. Which is a typical place for water-proofing rather than damp-proofing?
   A. Plinth wall
   B. Wall above ground
   C. Basement or roof
   D. Floor above ground
   Answer: C. Roofs, basements, tanks and terraces need waterproofing. (Key point: Application)

3. How does water-proofing compare with damp-proofing?
   A. Thinner and cheaper
   B. Same thickness, higher cost
   C. Thinner and costlier
   D. Thicker, multilayer and costlier
   Answer: D. Waterproofing is thicker, multilayer and high cost; damp-proofing is thin (20-40 mm) and low cost. (Key point: Thickness and cost)

## Related in Building Technology

- [Methods of damp proofing](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adamp-proofing-methods) — Building Technology, chapter 1, asked 2×
- [Damp proofing and defects due to moisture](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Adamp-proofing-defects) — Building Technology, chapter 1
- [Below and above grade water proofing](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Awaterproof-below-above-grade) — Building Technology, chapter 1
- [Positive and negative side water proofing](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Awaterproof-positive-negative) — Building Technology, chapter 1

## Related in other subjects

- [Fire tube versus water tube boilers](https://www.bctengineer.com/question.md?key=semester_3%2Fapplied_thermodynamics%3Afire-tube-water-tube-difference) — Applied Thermodynamics, chapter 1
- [Need of cooling; air versus water cooling](https://www.bctengineer.com/question.md?key=semester_6%2Finternal_combustion_engines%3Aengine-cooling-need-air-water-comparison) — Internal Combustion Engines, chapter 7