---
title: "Materials for brick wall 20 m (1:5)"
subject: "Estimating and Costing"
chapter: 4
key: "semester_7/estimating_and_costing:materials-brick-wall-20m"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/materials-brick-wall-20m
site: BCT Engineering
---

# Materials for brick wall 20 m (1:5)

Estimating and Costing · Chapter 4: Analysis of Rates

- Asked in: 2082 Baisakh, 5 marks
- Video: [Brick Quantity calculation for house | How to calculate sand & Cement for Brick work By CivilGuruji](https://www.youtube.com/watch?v=bFY5ZaOrY7U) — The Institute of Construction Managment 
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/materials-brick-wall-20m
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-4

## Question

Calculate quantities of material required for brick wall of a building L × B × H = 20 m × 0.23 m × 3 m with 10 mm thick in 1:5 mortar. The wall contains two windows of size 1.2 m × 1.2 m. Take standard size of brick.

## Short answer

Net masonry 20×0.23×3 m minus two 1.2×1.2 m openings = 13.1376 m³. Bricks (230×110×55 mm): 7018 nos. (7369 with 5% wastage). 1:5 mortar dry volume 4.3838 m³: cement 21.04 bags, sand 3.653 m³.

## Answer

#### Net volume of masonry
- Gross volume = 20 x 0.23 x 3 = 13.800 m³
- Openings = 2 x 1.2 x 1.2 x 0.23 = 0.6624 m³
- Net volume = 13.800 - 0.6624 = 13.1376 m³

#### Bricks
Using the standard brick 230 x 110 x 55 mm with 10 mm mortar joints, the nominal size is 240 x 120 x 65 mm.
$$
\text{Bricks per m}^3 = \frac{1}{0.240 \times 0.120 \times 0.065} = 534.19
$$
Number of bricks = 534.19 x 13.1376 = **7018 nos.** (about 7369 nos. with 5% wastage).

#### Mortar (1:5)
- Volume of bricks without mortar = 7018 x 0.23 x 0.11 x 0.055 = 9.7655 m³
- Wet mortar = 13.1376 - 9.7655 = 3.3721 m³
- Dry mortar = 3.3721 x 1.30 = 4.3838 m³
- Cement = 4.3838/6 = 0.7306 m³ = 1052.1 kg = **21.04 bags** (50 kg)
- Sand = 4.3838 x 5/6 = **3.653 m³**

**Answer: Bricks = 7018 nos.; cement = 21.04 bags (0.731 m³); sand = 3.653 m³.**

## Check yourself

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

1. How is net masonry volume found?
   A. Gross volume plus openings
   B. Gross volume only
   C. Gross volume minus volume of openings
   D. Openings only
   Answer: C. Windows are deducted. (Key point: Net volume)

2. How is number of bricks found?
   A. Gross volume x 534
   B. Net volume / 534
   C. Mortar x 534
   D. Bricks per m³ x net volume
   Answer: D. Bricks per m³ times net volume. (Key point: Bricks count)

3. How is wet mortar found?
   A. Net masonry volume minus volume of bricks alone
   B. Dry mortar x 1.3
   C. Net volume x 0.5
   D. Bricks x 1.3
   Answer: A. Remaining volume is mortar. (Key point: Wet mortar)

4. How to split dry mortar for 1:5?
   A. Cement = dry/5
   B. Cement = dry/6, sand = dry x 5/6
   C. Cement = dry/4
   D. Cement = dry x 5/6
   Answer: B. Ratio sum is 6. (Key point: Cement and sand)

## Close variants set in other exams

- [Materials for brick wall 10 m (1:5)](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Amaterials-brick-wall-10m-1-5) — Estimating and Costing, chapter 4, asked 2×

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