---
title: "Rate analysis: M20 PCC, raft foundation"
subject: "Estimating and Costing"
chapter: 4
key: "semester_7/estimating_and_costing:rate-m20-pcc-raft"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-m20-pcc-raft
site: BCT Engineering
---

# Rate analysis: M20 PCC, raft foundation

Estimating and Costing · Chapter 4: Analysis of Rates

- Asked in: 2080 Bhadra, 6 marks
- Video: [RATE ANALYSIS FOR CONCRETE ITEMS-SITE MIX](https://www.youtube.com/watch?v=Pj12GXLx7uQ) — civil conclave
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/rate-m20-pcc-raft
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-4

## Question

Prepare the rate analysis for M20 PCC work in 10 m × 10 m × 1 m raft foundation.

## Short answer

For nominal mix 1:1.5:3, dry volume factor 1.54. Per m3: cement 8.06 bags, sand 0.42 m3, aggregate 0.84 m3, skilled 1 md, unskilled 7 md. Rate = Rs 21,900.60 per m3; raft cost = Rs 2,190,060.

## Answer

#### Basis
Raft = 10 x 10 x 1 = **100 m³** of M20 concrete (nominal mix 1:1.5:3, IS 456 Table 9). Dry volume = 1.54 x wet volume. Rates are **illustrative**; mixing is manual (a concrete mixer would be preferred for this volume and would reduce the labour).

#### Quantities per m³
- Cement = 1.54/5.5 = 0.2800 m³ = 8.06 bags
- Sand = 1.54 x 1.5/5.5 = 0.4200 m³
- Aggregate = 1.54 x 3/5.5 = 0.8400 m³

#### Rate analysis (per m³)
| Description | Qty | Unit | Rate (Rs) | Amount (Rs) |
|---|---|---|---|---|
| Cement (0.2800 m³) | 8.06 | bag | 900.00 | 7,254.00 |
| Sand (0.420 m³) | 0.42 | m³ | 2,500.00 | 1,050.00 |
| Aggregate 20 mm (0.840 m³) | 0.84 | m³ | 3,500.00 | 2,940.00 |
| Mason (skilled) | 1 | md | 1,200.00 | 1,200.00 |
| Labour (unskilled) | 7 | md | 900.00 | 6,300.00 |
| Water, curing, tools (L.S.) | 1 | L.S. | 300.00 | 300.00 |
| **Sub-total** | | | | **19,044.00** |
| Contractor's overhead and profit | 15% | | | 2,856.60 |
| **Rate per m³** | | | | **21,900.60** |

#### Quantities and cost for the raft (100 m³)
- Cement = 806.4 bags; sand = 42.0 m³; aggregate = 84.0 m³
- Skilled labour = 100 md; unskilled = 700 md
- Cost = 100 x 21,900.60 = Rs 2,190,060.00

**Answer: Rate of M20 PCC = Rs 21,900.60 per m³; cost of the 100 m³ raft concrete = Rs 2,190,060.00** (excluding formwork, reinforcement and VAT).

## Check yourself

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

1. Which nominal mix is used for M20 concrete?
   A. 1:1:2
   B. 1:2:4
   C. 1:3:6
   D. 1:1.5:3
   Answer: D. M20 corresponds to the nominal mix 1:1.5:3 as per IS 456 Table 9. (Key point: Nominal mix)

2. With dry volume 1.54 m^3 per m^3 of wet concrete and ratio sum 5.5, what is the cement volume per m^3?
   A. 1/5.5 = 0.182 m^3
   B. 1.54/6 = 0.257 m^3
   C. 1.54/5.5 = 0.28 m^3 (8.06 bags)
   D. 1.54 x 1.5/5.5 = 0.42 m^3
   Answer: C. Cement is 1 part in 5.5, so 1.54/5.5 = 0.28 m^3, which is 8.06 bags. (Key point: Cement per m^3)

3. What is the raft concrete volume used for total cost?
   A. 10 m^3
   B. 100 m^3 (10 x 10 x 1)
   C. 154 m^3 (dry volume)
   D. 300 m^3
   Answer: B. Raft = 10 x 10 x 1 = 100 m^3, so cost = 100 x Rs 21,900.60. (Key point: Raft quantity)

4. How is the Rs 21,900.60 rate per m^3 reached from the sub-total Rs 19,044?
   A. Add 15% contractor's overhead and profit (Rs 2,856.60)
   B. Add VAT of 13%
   C. Add 15% to material cost only
   D. Subtract wastage of 15%
   Answer: A. The sub-total is increased by 15% contractor's overhead and profit: 19,044 + 2,856.60 = 21,900.60 (VAT excluded). (Key point: Overhead and profit)

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## Related in other subjects

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