---
title: "Building: excavation, brick, plaster (18 marks)"
subject: "Estimating and Costing"
chapter: 6
key: "semester_7/estimating_and_costing:building-t-fig-four-items"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/building-t-fig-four-items
site: BCT Engineering
---

# Building: excavation, brick, plaster (18 marks)

Estimating and Costing · Chapter 6: Detailed Estimate

- Asked in: 2067 Poush (old course), 18 marks
- Video: [(Part I: Earthwork) Estimation of two roomed building (long wall short wall method)](https://www.youtube.com/watch?v=4x4oRRwJb3s) — CIVIL ENGINEERING By Karthivelu S
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/building-t-fig-four-items
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6

## Question

Estimate the quantities of the following items of work from the accompanying drawing:
a) Earth work in excavation in foundation
b) Brick work in foundation and plinth
c) Inside wall and ceiling cement plaster
d) Brick work in superstructure
[Drawing: plan 7230 mm × 3730 mm; 230 mm walls; two rooms with 3270 mm clear spans, 3500 mm bays; doors D 1200 × 2100, D1 1000 × 2100; windows W 1200 × 1200, W1 1200 × 1200; section X-X: roof slab with 18 screed over two layers of tarfelt, 600 mm projection, window 3270 wide, heights 2100/2400/1200/900, DPC, floor: 3 cement sand (1:1) pointing over 36 cement concrete (1:2:4), 75 thick brick bats soling, 150 sand filling; foundation 770 mm wide PCC (1:3:6) with footings, layers 150/250/150/150/80 mm.]

## Short answer

Centre-line outer walls 21.00 m, partition shortened at junctions; deductions for openings made. Quantities: excavation 14.62 m³, foundation and plinth brickwork 9.67 m³, inside wall and ceiling plaster 73.13 m², superstructure brickwork 11.34 m³.

## Answer

#### Reading of the drawing
Plan: two rooms 3.27 × 3.27 m clear with 230 mm walls (overall 7.23 × 3.73 m, matching the given 7230 × 3730). Centre-line of the outer walls = 2[(7.23 − 0.23) + (3.73 − 0.23)] = 21.00 m. The central partition is 3.27 + 0.23 = 3.50 m between the outer-wall centre lines; at its two T-junctions it is shortened by half the width of the outer-wall item at each end: trench 3.50 − 0.77 = 2.73 m, step 1 3.50 − 0.69 = 2.81 m, step 2 3.50 − 0.46 = 3.04 m, wall 3.50 − 0.23 = 3.27 m.

Foundation section as marked: PCC 1:3:6 0.77 m wide × 0.15 m, brick step 0.69 × 0.25 m, brick step 0.46 × 0.15 m, 230 mm wall; assumed trench depth 0.80 m; plinth 0.45 m above GL (floor 150 mm sand, 75 mm brick soling, concrete, 1:1 pointing). Wall height 2.4 m above plinth, with door D 1.2 × 2.1 (1), D1 1.0 × 2.1 (1, between rooms), W 1.2 × 1.2 (2), W1 1.2 × 1.2 (1). Plaster 12 mm.

#### a) Earthwork in excavation in foundation
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Trench, outer walls | 1 | 21.000 | 0.770 | 0.800 | 12.936 |
| Trench, partition (3.50 − 0.77) | 1 | 2.730 | 0.770 | 0.800 | 1.682 |
| **Total** | | | | | **14.618** |

#### b) Brickwork in foundation and plinth
Wall height above step 2 = 0.80 − 0.15 − 0.25 − 0.15 + 0.45 = 0.70 m.

| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Brick step 0.69 × 0.25 (21.00 + 2.81) | 1 | 23.810 | 0.690 | 0.250 | 4.107 |
| Brick step 0.46 × 0.15 (21.00 + 3.04) | 1 | 24.040 | 0.460 | 0.150 | 1.659 |
| Wall 0.23 × 0.70 to plinth (21.00 + 3.27) | 1 | 24.270 | 0.230 | 0.700 | 3.907 |
| **Total** | | | | | **9.673** |

#### c) Inside wall and ceiling cement plaster
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m²) |
|---|---|---|---|---|---|
| Inside walls 2 rooms × 2(3.27+3.27) × 2.4 | 1 | 26.160 | 2.400 | – | 62.784 |
| Deduct D (one face) | -1 | 1.200 | 2.100 | – | -2.520 |
| Deduct D1 (both faces) | -2 | 1.000 | 2.100 | – | -4.200 |
| Deduct windows W 1.2×1.2 (2) and W1 (1) | -3 | 1.200 | 1.200 | – | -4.320 |
| Ceiling 2 rooms × 3.27 × 3.27 | 2 | 3.270 | 3.270 | – | 21.386 |
| **Total** | | | | | **73.130** |

#### d) Brickwork in superstructure
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Wall 0.23 × 2.4 above plinth | 1 | 24.270 | 0.230 | 2.400 | 13.397 |
| Deduct D 1.2×2.1 | -1 | 1.200 | 0.230 | 2.100 | -0.580 |
| Deduct D1 1.0×2.1 | -1 | 1.000 | 0.230 | 2.100 | -0.483 |
| Deduct W 1.2×1.2 | -2 | 1.200 | 0.230 | 1.200 | -0.662 |
| Deduct W1 1.2×1.2 | -1 | 1.200 | 0.230 | 1.200 | -0.331 |
| **Total** | | | | | **11.341** |

**Answer:** Excavation 14.62 m³; foundation and plinth brickwork 9.67 m³; plaster (walls and ceiling) 73.13 m²; superstructure brickwork 11.34 m³.

## Check yourself

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

1. Trench 0.80 m, PCC 0.15 m, steps 0.25 m and 0.15 m, plinth 0.45 m above GL. What is the wall height above step 2?
   A. 0.70 m
   B. 0.25 m
   C. 1.15 m
   D. 0.95 m
   Answer: A. 0.80 - 0.15 - 0.25 - 0.15 = 0.25 m below ground, plus 0.45 m = 0.70 m. (Key point: Wall height above step 2)

2. In the inside plaster, why is door D deducted once and D1 twice?
   A. D1 is wider than D
   B. D is an external door seen from inside once; D1 is in the partition and appears on both room faces
   C. D1 has two shutters
   D. D is plastered on one side only because it is wooden
   Answer: B. Inside plaster is measured on room faces only: the external door has one inner face, the partition door has two. (Key point: Plaster door deductions)

3. Inside walls are 2 rooms x 2(3.27 + 3.27) x 2.4 = 62.784 m2. What does this mean for the partition?
   A. Each room's perimeter includes the partition face, so both faces are plastered
   B. The partition is plastered only once
   C. The partition is not plastered
   D. The partition is added separately as 3.27 x 2.4
   Answer: A. Taking the perimeter of each room separately includes the partition once for each room, giving both faces. (Key point: Wall plaster per room)

4. What is the deduction for two windows W of 1.2 x 1.2 m in the 0.23 m wall?
   A. 0.331 m3
   B. 0.828 m3
   C. 2 x 1.2 x 0.23 x 1.2 = 0.662 m3
   D. 0.580 m3
   Answer: C. Each opening is deducted at wall thickness: 1.2 x 0.23 x 1.2 = 0.331 m3, and for two windows 0.662 m3. (Key point: Window deduction in superstructure)

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