---
title: "Structural and non-structural cracks"
subject: "Building Technology"
chapter: 10
key: "semester_6/building_technology:cracks-structural-nonstructural"
source: https://www.bctengineer.com/q/semester_6/building_technology/cracks-structural-nonstructural
site: BCT Engineering
---

# Structural and non-structural cracks

Building Technology · Chapter 10: Causes and prevention of cracks in buildings

- Asked in: 2079 Asoj, 4 marks; 2078 Poush, 4 marks; 2076 Bhadra, 4 marks; 2072 Magh, 8 marks (asked 4 times)
- Video: [Types of cracks in building |  Structural crack and Non structural cracks in building | Crack remedy](https://www.youtube.com/watch?v=ez-O6c4BqRQ) — Civil Engineering Mastery
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/cracks-structural-nonstructural
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-10

## Question

Write short notes on structural and non-structural cracks in the building.

## Short answer

Structural cracks are wide, progressive, through-thickness, caused by overloading, settlement, design faults, corrosion; they threaten stability and require strengthening (epoxy injection, jacketing). Non-structural cracks are hairline, from shrinkage, thermal, moisture effects; they affect appearance and durability, repaired by surface sealing or plastering.

## Answer

#### Structural cracks
Structural cracks occur from faults in design, construction or loading that affect the strength and stability of the structure. They are wide, progressive and often pass through the full thickness.

- **Causes:** overloading, differential foundation settlement, poor design or detailing, shear and bending failure, corrosion of reinforcement, earthquake, defective materials.
- **Appearance:** diagonal or step cracks near supports, vertical cracks in the middle of beams, cracks near column-beam joints, cracks at the soffit of slabs.
- **Danger:** may cause collapse. They need immediate investigation and repair.

#### Non-structural cracks
Non-structural cracks come from internal stresses in building materials. They do not affect the strength directly but allow water entry and look bad.

- **Causes:** shrinkage, thermal expansion, moisture movement, chemical reaction, poor curing, vegetation.
- **Appearance:** fine, hairline, random (map) cracks, in plaster, floors and walls.
- **Remedy:** cement slurry or sealant, fresh plaster, expansion joints.

| Point | Structural | Non-structural |
|---|---|---|
| Cause | Loads, settlement, design faults | Shrinkage, temperature, moisture |
| Width | Wide, growing | Narrow, usually stable |
| Danger | Affects stability | Affects appearance, durability |
| Repair | Strengthening, grouting, jacketing | Filling, plaster |

## Check yourself

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

1. Structural cracks are mainly those that:
   A. Result from faults in design, construction or loading and affect stability
   B. Appear only in paint
   C. Are caused only by shrinkage of plaster
   D. Are always hairline and stable
   Answer: A. They affect strength and stability and are wide and progressive. (Key point: Meaning of structural cracks)

2. Which is a typical cause of non-structural cracks?
   A. Overloading
   B. Drying shrinkage and thermal or moisture movement
   C. Differential foundation settlement
   D. Shear failure of beams
   Answer: B. Non-structural cracks come from internal stresses such as shrinkage and temperature. (Key point: Non-structural cause)

3. Which crack pattern points to a structural problem?
   A. Fine map cracks in plaster
   B. Hairline cracks in paint
   C. Diagonal or step cracks near supports
   D. Random surface crazing
   Answer: C. Diagonal/step cracks near supports and vertical cracks mid-beam indicate structural distress. (Key point: Appearance)

4. Why must structural cracks be investigated immediately?
   A. They only spoil appearance
   B. They stop water entry
   C. They always heal themselves
   D. They may lead to collapse
   Answer: D. They affect stability and may cause collapse; non-structural ones mostly affect appearance and durability. (Key point: Danger and action)

## Related in Building Technology

- [Structural vs non-structural cracks and causes](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acracks-struct-nonstruct-causes) — Building Technology, chapter 10
- [Causes of cracks in a building](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acauses-of-cracks) — Building Technology, chapter 10, asked 3×
- [Methods of repairing cracks](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acrack-repair-methods) — Building Technology, chapter 10, asked 3×
- [Causes and remedies of cracks](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acracks-causes-remedial) — Building Technology, chapter 10, asked 2×
- [Reasons for cracks in plastering](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aplaster-crack-reasons) — Building Technology, chapter 9
- [Painting on masonry; causes and remedies of cracks](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apainting-masonry-cracks) — Building Technology, chapter 9

## Related in other subjects

- [Non-linearity in structural analysis](https://www.bctengineer.com/question.md?key=semester_4%2Ftheory_of_structures_i%3Anonlinearity-structural-analysis) — Theory of Structures I, chapter 1