---
title: "Characteristics of good timber"
subject: "Civil Engineering Materials"
chapter: 7
key: "semester_3/civil_engineering_materials:characteristics-good-timber"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/characteristics-good-timber
site: BCT Engineering
---

# Characteristics of good timber

Civil Engineering Materials · Chapter 7: Timber

- Asked in: 2080 Bhadra, 2 marks; 2071 Chaitra, 2 marks; 2068 Chaitra, 3 marks (asked 3 times)
- Video: [Characteristics of Good Timber | Properties of Timber | Civil Engineering | Construction Materials](https://www.youtube.com/watch?v=HmKdg0atUAg) — Polytechnic Class (READBY) 
- 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-timber
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-7

## Question

What are the characteristics of good timber useful for engineering purpose?

## Short answer

Good engineering timber has uniform dark colour, compact grain, narrow annual rings, and high strength; it is well-seasoned (10–15% moisture), durable, tough, dimensionally stable, and easy to work.

## Answer

Good timber for engineering use should have these characteristics:

1. **Colour and appearance:** uniform, dark colour in heartwood; shining surface when cut; sweet smell, with clear ringing sound when struck.
2. **Structure:** compact, fine and uniform grain, regular annual rings with narrow width, dense medullary rays, and a hard texture.
3. **Sound heartwood:** timber from mature trees (not young or old) with a high proportion of heartwood.
4. **Free from defects:** no knots, shakes, cracks, decay or insects.
5. **Strength:** high strength in compression, bending and shear; resilient and tough.
6. **Seasoned:** low moisture content (10-15%).
7. **Durable:** resistant to fungi, insects, and moisture changes; weathers well.
8. **Elasticity and hardness:** good elasticity, high hardness to resist wear.
9. **Workability:** easy to saw, plane, nail and polish; takes paint well.
10. **Dimensionally stable:** small shrinkage and swelling; no warping.
11. **Fire resistance, weight:** heavy species are generally stronger; adequate resistance to fire.

## Check yourself

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

1. Good timber has a grain that is
   A. Coarse and irregular
   B. Wide-ringed and open
   C. Spongy with many knots
   D. Compact, fine and uniform with narrow regular annual rings
   Answer: D. Fine uniform structure indicates good timber. (Key point: Structure)

2. A good piece of timber when struck gives
   A. A clear ringing sound
   B. A dull thud
   C. A hollow rattle
   D. No sound
   Answer: A. Sound timber rings clearly. (Key point: Sound test)

3. Good timber for engineering use should have moisture content of
   A. 30-40%
   B. 10-15%
   C. 20-25% green
   D. Above 50%
   Answer: B. It should be well seasoned. (Key point: Moisture)

4. Good timber should be
   A. Rich in knots for strength
   B. Taken from very young trees
   C. Free from knots, shakes, decay and insects
   D. Fresh and sappy
   Answer: C. Defects reduce strength. (Key point: Defects)

## Related in Civil Engineering Materials

- [Characteristics of good building stones](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acharacteristics-good-building-stones) — Civil Engineering Materials, chapter 2, asked 9×
- [Characteristics of good bricks](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acharacteristics-good-bricks) — Civil Engineering Materials, chapter 3, asked 4×
- [Characteristics of good brick earth](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acharacteristics-good-brick-earth) — Civil Engineering Materials, chapter 3
- [Characteristics of a good paint](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acharacteristics-good-paint) — Civil Engineering Materials, chapter 9
- [Characteristics of good varnishes](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Acharacteristics-good-varnish) — Civil Engineering Materials, chapter 9
- [Seasoning of timber and its necessity](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aseasoning-meaning-necessity) — Civil Engineering Materials, chapter 7, asked 8×

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