---
title: "Materials: 105 m³ PCC 1:4:8, 725 m² plaster"
subject: "Estimating and Costing"
chapter: 4
key: "semester_7/estimating_and_costing:materials-pcc-plaster-r"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/materials-pcc-plaster-r
site: BCT Engineering
---

# Materials: 105 m³ PCC 1:4:8, 725 m² plaster

Estimating and Costing · Chapter 4: Analysis of Rates

- Asked in: 2068 Baisakh (old course), 3×2 marks
- 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-pcc-plaster-r
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-4

## Question

Calculate the quantities of materials required for the following items of work: i) 105 m³ of PCC (1:4:8) in foundation ii) 725 m² of 20 mm thick cement plaster (1:4) in wall.

## Short answer

i) 105 m³ PCC (1:4:8) with dry factor 1.54: cement 358.2 bags, sand 49.75 m³, aggregate 99.51 m³. ii) 725 m² of 20 mm plaster (1:4) with dry factor 1.27: cement 106.1 bags, sand 14.73 m³.

## Answer

Assumptions: dry volume = 1.54 × wet volume for concrete and 1.27 × wet volume for mortar; 1 m³ of cement = 28.8 bags of 50 kg; no wastage is added.

#### (i) 105 m³ PCC (1:4:8) in foundation

- Wet volume $= 105.000$ m³; dry volume $= 1.54 \times 105.000 = 161.700$ m³ (sum of ratio $= 13$)
- Cement $= 1/13 \times 161.700 = 12.438$ m³ $= 12.438 \times 28.8 = 358.2$ bags (50 kg)
- Sand $= 4/13 \times 161.700 = 49.754$ m³
- Coarse aggregate $= 8/13 \times 161.700 = 99.508$ m³

#### (ii) 725 m² of 20 mm plaster (1:4)

- Wet mortar $= 725.0 \times 0.0200 = 14.5000$ m³; dry volume $= 1.27 \times 14.5000 = 18.4150$ m³
- Cement $= 1/5 \times 18.4150 = 3.6830$ m³ $= 106.07$ bags
- Sand $= 4/5 \times 18.4150 = 14.7320$ m³

**Answer: (i) cement 358.2 bags, sand 49.75 m³, aggregate 99.51 m³. (ii) cement 106.1 bags, sand 14.73 m³.**

## Check yourself

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

1. 1:4:8 sum?
   A. 12
   B. 8
   C. 13
   D. 5
   Answer: C. 1+4+8. (Key point: Ratio sum)

2. Cement for 105 m^3?
   A. 1/13 x 105
   B. 1/13 x 161.7 = 12.438 m^3 = 358.2 bags
   C. 1/12 x 161.7
   D. 1/8 x 161.7
   Answer: B. Dry 1.54 x 105. (Key point: Cement)

3. Wet mortar for 725 m^2 at 20 mm?
   A. 14.5 m^3
   B. 18.4 m^3
   C. 7.25
   D. 145
   Answer: A. 725 x 0.02. (Key point: Plaster wet)

4. Cement?
   A. 1/4
   B. 1/5 of 14.5
   C. 4/5
   D. 1/5 x 18.415 = 3.683 m^3 = 106.1 bags
   Answer: D. Sum 5. (Key point: Plaster cement)

## Close variants set in other exams

- [Materials: 115 m² PCC floor, 110 m² plaster](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Amaterials-pcc-floor-plaster-i) — Estimating and Costing, chapter 4, asked 2×

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