---
title: "Functions and properties of mortar"
subject: "Building Technology"
chapter: 3
key: "semester_6/building_technology:mortar-functions-properties"
source: https://www.bctengineer.com/q/semester_6/building_technology/mortar-functions-properties
site: BCT Engineering
---

# Functions and properties of mortar

Building Technology · Chapter 3: Mortars & Masonry works

- Asked in: 2076 Bhadra, 4 marks
- Video: [Mortar Qualities and properties](https://www.youtube.com/watch?v=i505PjQegmA) — construct SKILLS
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/mortar-functions-properties
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-3

## Question

Explain in brief functions and properties of mortar.

## Short answer

Functions: binding units, spreading loads, filling gaps, providing a level bed, decoration. Properties: good workability, water retentivity, adhesion, adequate compressive strength, durability, low shrinkage, impermeability.

## Answer

#### Functions of mortar
1. Binds bricks or stones together into a single unit.
2. Spreads the load evenly over the bedding of the units.
3. Fills the gaps between units, so wind and rain cannot enter.
4. Gives a level bed so that the masonry is straight and plumb.
5. Gives a decorative effect in plaster and pointing, and protects the wall surface.
6. Takes up small movements and gives bond strength.

#### Properties of good mortar
- **Workability:** easy to mix and spread; remains plastic long enough to lay the unit.
- **Water retentivity:** keeps its water long enough, so bricks do not suck it out.
- **Adhesion:** good bond to bricks and stones.
- **Strength:** adequate compressive strength (cement mortar 1:4 about 7.5 N/mm² at 28 days).
- **Durability:** resists weather and chemical attack.
- **Setting:** should set neither too fast nor too slow.
- **Low shrinkage:** no cracks on drying.
- **Impermeability** and low cost.

## Check yourself

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

1. A function of mortar is to:
   A. Cool the room
   B. Remove water
   C. Increase weight only
   D. Spread load evenly over the bedding of units
   Answer: D. Also binds units and fills gaps. (Key point: Function)

2. Mortar gives:
   A. Steel
   B. Rough walls
   C. No help
   D. A level bed so masonry is plumb and straight
   Answer: D. A level bed keeps courses straight. (Key point: Level bed)

3. Mortar should set:
   A. Instantly
   B. After a week
   C. Never
   D. Neither too fast nor too slow
   Answer: D. Proper setting time allows placing then hardening. (Key point: Setting)

## Related in Building Technology

- [Properties of mortar](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aproperties-of-mortar) — Building Technology, chapter 3, asked 3×
- [Mortar properties; cement and sand for 10 cum](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-quantity-10cum) — Building Technology, chapter 3

## Related in other subjects

- [Define mortar in brief](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Adefine-mortar) — Civil Engineering Materials, chapter 6, asked 4×
- [Functions of mortar](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Afunctions-of-mortar) — Civil Engineering Materials, chapter 6, asked 8×
- [Surkhi mortar in brief](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Asurkhi-mortar) — Civil Engineering Materials, chapter 6, asked 2×
- [Gauged mortar in brief](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Agauged-mortar) — Civil Engineering Materials, chapter 6, asked 2×