---
title: "Characteristics of good bricks"
subject: "Civil Engineering Materials"
chapter: 3
key: "semester_3/civil_engineering_materials:characteristics-good-bricks"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/characteristics-good-bricks
site: BCT Engineering
---

# Characteristics of good bricks

Civil Engineering Materials · Chapter 3: Clay Products

- Asked in: 2073 Shrawan, 2 marks; 2071 Chaitra, 2 marks; 2059 Poush (old course), 4 marks; 2070 Chaitra (old course), 5 marks (asked 4 times)
- Video: [QUALITIES OF GOOD BRICK](https://www.youtube.com/watch?v=xtKMr1tibWw) — Architects Academy
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/characteristics-good-bricks
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-3

## Question

What are the characteristics (qualities/properties) of a good brick?

## Short answer

A good brick has uniform cherry-red colour, standard size 240×115×57 mm, compact fine-grained structure, metallic ring when struck, no nail scratch, compressive strength ≥3.5 N/mm², water absorption <20%, no efflorescence, and a rough surface for mortar bond.

## Answer

A good brick has the following characteristics.

1. **Shape and size:** well burnt, with a regular rectangular shape, sharp edges and plane faces. The Nepal Standard size is 240 × 115 × 57 mm (the IS modular size is 190 × 90 × 90 mm).
2. **Colour:** uniform, bright cherry red.
3. **Structure:** homogeneous and compact, with fine grains, and free from cracks, voids, lumps of lime and stones.
4. **Sound:** gives a clear metallic ringing sound when two bricks are struck together.
5. **Hardness:** a fingernail makes no mark.
6. **Strength:** compressive strength not less than 3.5 N/mm² (higher for load-bearing and machine-made bricks).
7. **Water absorption:** not more than 20% of dry weight after 24 hours of immersion.
8. **Efflorescence:** nil or only slight.
9. **Durability:** should withstand weathering, fire and frost.
10. **Weight and thermal behaviour:** light in weight, and a poor conductor of heat and sound.
11. **Mortar bond:** the surface should have a rough texture for a proper bond with mortar.

## Check yourself

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

1. Minimum compressive strength of a good brick:
   A. 0.35 N/mm^2
   B. 35 N/mm^2
   C. 3.5 N/mm^2
   D. 1.0 N/mm^2
   Answer: C. Not less than 3.5 N/mm^2, higher for load-bearing. (Key point: Strength)

2. A good brick should be a:
   A. Good conductor of heat
   B. Good conductor of sound
   C. Good conductor of electricity
   D. Poor conductor of heat and sound
   Answer: D. Brick gives thermal and sound insulation. (Key point: Thermal)

3. Why should brick surface be rough?
   A. For proper bond with mortar
   B. To reduce weight
   C. To improve ring sound
   D. To reduce absorption
   Answer: A. Rough texture bonds well with mortar. (Key point: Surface for bond)

## Related in Civil Engineering Materials

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- [Floor tiles and over burnt brick](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Agood-floor-tiles-overburnt-brick) — Civil Engineering Materials, chapter 3

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