---
title: "Suitability and properties of timber"
subject: "Civil Engineering Materials"
chapter: 7
key: "semester_3/civil_engineering_materials:timber-suitability-properties"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/timber-suitability-properties
site: BCT Engineering
---

# Suitability and properties of timber

Civil Engineering Materials · Chapter 7: Timber

- Asked in: 2074 Asoj, 2+1 marks
- Video: [Timbers - Classification, Properties and Uses](https://www.youtube.com/watch?v=zfK7TLobsv0) — Mr Everett's Design and Technology Workshop
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/timber-suitability-properties
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-7

## Question

Describe the suitability of timber in the design of civil engineering structures. List the engineering properties of timber.

## Short answer

Timber suits roofs (rafters, trusses), floors, doors, formwork, scaffolding, light bridges, and piles. Its engineering properties include tensile, compressive, bending and shear strength along and across grain, modulus of elasticity, hardness, density, moisture content, durability, shrinkage, workability, and thermal/acoustic insulation.

## Answer

#### Suitability of timber in structures
Timber is suitable for:
- **Roof structures:** rafters, purlins, trusses, battens for small and medium spans.
- **Floors and partitions:** joists, floorboards, panelling.
- **Doors, windows and frames.**
- **Formwork, scaffolding and shoring** for concrete work.
- **Bridges and piles** (light bridges, and timber piles under water, with preservation).
- **Furniture and fittings.**

It suits the structures in which light weight, quick erection, insulation and ease of working matter, and where members are protected from moisture and fire. It should be properly seasoned and treated, and designed on allowable stresses of the species and grade (IS 883).

#### Engineering properties
1. Strength in tension, compression, bending, shear and impact (along and across grain).
2. Modulus of elasticity and stiffness.
3. Hardness and toughness.
4. Density (specific gravity) and moisture content.
5. Durability against fungi, insects and weather.
6. Shrinkage and swelling.
7. Workability and finishing property.
8. Thermal, acoustic and electrical insulation.

## Check yourself

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

1. Timber suits structures where
   A. Light weight, quick erection and ease of working matter and members are protected from moisture and fire
   B. Exposure to fire
   C. Heavy loads on long spans
   D. Constant wetting
   Answer: A. As stated. (Key point: Suitability)

2. Timber should be designed on
   A. Steel stresses
   B. Allowable stresses of the species and grade (IS 883)
   C. Concrete grades
   D. Guesses
   Answer: B. IS 883. (Key point: Design)

3. Timber is used for
   A. Only reinforcement
   B. Only pipes
   C. Roof trusses, floors, formwork, doors
   D. Nothing structural
   Answer: C. Several uses. (Key point: Uses)

4. Engineering properties include
   A. Only colour
   B. Only price
   C. Only smell
   D. Strength, elasticity, hardness, density, moisture, shrinkage
   Answer: D. Listed. (Key point: Properties)

## Related in Civil Engineering Materials

- [Important properties of civil engineering materials](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aimportant-properties-civil-materials) — Civil Engineering Materials, chapter 1, asked 8×
- [Importance and scope of civil engineering materials](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aimportance-scope-subject) — Civil Engineering Materials, chapter 1, asked 8×
- [Classification of civil engineering materials](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aclassification-civil-materials) — Civil Engineering Materials, chapter 1, asked 2×
- [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×
- [Methods of preserving timber](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Apreservation-of-timber) — Civil Engineering Materials, chapter 7, asked 4×
- [Defects of timber](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Adefects-of-timber) — Civil Engineering Materials, chapter 7, asked 4×

## Related in other subjects

- [Design methods and basis for timber structures](https://www.bctengineer.com/question.md?key=semester_6%2Fdesign_of_steel_and_timber_structure%3Atimber-design-methods-basis) — Design of Steel and Timber Structure, chapter 9
- [Steel versus timber structures](https://www.bctengineer.com/question.md?key=semester_6%2Fdesign_of_steel_and_timber_structure%3Asteel-vs-timber-advantages) — Design of Steel and Timber Structure, chapter 1
- [Folds: recognition and civil engineering influence](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Afolds-recognition-and-civil-engineering) — Engineering Geology I, chapter 5
- [Scope and importance of geology in civil engineering](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Ascope-and-importance-of-geology) — Engineering Geology I, chapter 1, asked 24×