---
title: "Efflorescence test for bricks"
subject: "Civil Engineering Materials"
chapter: 3
key: "semester_3/civil_engineering_materials:efflorescence-test-brick"
source: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/efflorescence-test-brick
site: BCT Engineering
---

# Efflorescence test for bricks

Civil Engineering Materials · Chapter 3: Clay Products

- Asked in: 2068 Baisakh, 2 marks
- Video: [Efflorescence Test of Bricks Explained | How to Perform Efflorescence Test of Bricks](https://www.youtube.com/watch?v=9-727_BWNMY) — Civil Edify
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/civil_engineering_materials/efflorescence-test-brick
- Whole chapter: https://www.bctengineer.com/md/semester_3/civil_engineering_materials/chapter-3

## Question

Describe briefly the test for efflorescence for bricks.

## Short answer

The brick is placed upright in 25 mm of distilled water. After water is absorbed and evaporated, more water is added and evaporated again, then the brick is examined for white salt deposits, rated nil, slight, moderate, heavy, or serious.

## Answer

The brick is placed on end in a shallow dish containing about 25 mm of distilled water, in a well ventilated room. After all water is absorbed and evaporated, the same quantity of water is added again and allowed to evaporate. The brick is then checked for white salt deposits.

**Rating:** nil (no deposit), slight (up to 10% of surface covered), moderate (10-50%), heavy (more than 50% with no powdering) and serious (powdering and flaking). A good brick should show not more than slight efflorescence.

## Check yourself

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

1. In the efflorescence test, water is added:
   A. Again after all water has evaporated
   B. Only once
   C. Continuously
   D. Never
   Answer: A. The same quantity is added a second time. (Key point: Procedure)

2. Moderate efflorescence covers:
   A. Up to 10%
   B. 10-50% of the surface
   C. More than 50%
   D. 0%
   Answer: B. Slight is up to 10%; heavy is over 50%. (Key point: Rating)

3. A good brick shows:
   A. Heavy
   B. Serious
   C. Not more than slight efflorescence
   D. Powdering
   Answer: C. Only nil or slight is acceptable. (Key point: Acceptance)

## Related in Civil Engineering Materials

- [Efflorescence in bricks](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aefflorescence-in-brick) — Civil Engineering Materials, chapter 3, asked 2×
- [Efflorescence causes and test](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aefflorescence-causes-lab-test) — Civil Engineering Materials, chapter 3

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- [Compressive strength test and classification of bricks](https://www.bctengineer.com/question.md?key=semester_5%2Fdesign_of_timber_and_masonry_structures%3Abrick-compressive-strength-test-classification) — Design of Timber and Masonry Structures, chapter 8
- [Compressive strength test of brick wall](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acompressive-test-masonry-wall) — Concrete Technology and Masonry Structure, chapter 10, asked 4×