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

# Structural vs non-structural cracks and causes

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

- Asked in: 2073 Magh
- 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-struct-nonstruct-causes
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-10

## Question

Differentiate between structural and non-structural cracks and with the help of neat sketches. Write down its causes of occurrence.

## Short answer

Structural cracks are wide (>1 mm), growing, and caused by overloading, settlement, design faults, or corrosion, threatening stability. Non-structural cracks are narrow, hairline, stable, caused by shrinkage, temperature changes, or poor curing, mainly affecting appearance.

## Answer

| Point | Structural cracks | Non-structural cracks |
|---|---|---|
| Meaning | Cracks due to faults affecting strength and stability | Cracks due to internal stresses in materials |
| Width | Wide (often > 1 mm), growing | Narrow, hairline, stable |
| Causes | Overloading, settlement, design faults, earthquake, corrosion | Shrinkage, temperature, moisture, poor curing |
| Pattern | Diagonal, step, vertical through thickness | Random, map type, horizontal in plaster |
| Danger | Can cause collapse | Mostly appearance, durability |
| Repair | Epoxy injection, jacketing, underpinning | Cement slurry, filling, new plaster |

```text
 Structural (settlement)     Non-structural (shrinkage)
  _______________              _______________
 |  \  step crack |           | ~~ map cracks  |
 |   \_           |           |  ~~            |
 |     \_  wide   |           |                |
 |_______\________|           |________________|
   foundation settles
```

#### Causes
**Structural:** overloading, unequal settlement of foundations, poor design and detailing, shear and bending failure, corrosion of steel, earthquake and wind, early removal of formwork.
**Non-structural:** drying shrinkage of mortar, plaster and concrete, thermal expansion and contraction, moisture movement of bricks, chemical action (sulphate attack), vegetation, poor materials and workmanship.

## Check yourself

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

1. Structural cracks are usually:
   A. Only in paint
   B. Hairline and stable
   C. Wide (often > 1 mm) and growing
   D. Random map cracks
   Answer: C. Width and growth are key differences. (Key point: Width)

2. Map-type random cracks in plaster are typically:
   A. Structural
   B. Caused by settlement
   C. Caused by overloading
   D. Non-structural, from shrinkage
   Answer: D. Shrinkage gives random map cracks. (Key point: Non-structural pattern)

3. A structural crack cause is:
   A. Unequal foundation settlement
   B. Drying shrinkage of plaster
   C. Poor paint
   D. Plaster curing
   Answer: A. Settlement, overload and design faults cause structural cracks. (Key point: Structural cause)

## Related in Building Technology

- [Structural and non-structural cracks](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acracks-structural-nonstructural) — Building Technology, chapter 10, asked 4×
- [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×
- [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×
- [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

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