---
title: "Building: excavation, PCC foundation, brick"
subject: "Estimating and Costing"
chapter: 6
key: "semester_7/estimating_and_costing:building-q-three-items"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/building-q-three-items
site: BCT Engineering
---

# Building: excavation, PCC foundation, brick

Estimating and Costing · Chapter 6: Detailed Estimate

- Asked in: 2070 Chaitra, 5+4+5 marks
- Video: [Learn Quantity Surveying|Calculation Earth work, Concrete, Brick work In foundation, Plinth and DPC.](https://www.youtube.com/watch?v=1s_b4cNeS1U) — Civil Engineering Survey
- 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-q-three-items
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6

## Question

Prepare a detailed estimate of the following items of work of a building (drawing attached herewith)
i) Earth work in excavation
ii) PCC (1:3:6) in foundation
iii) Brick work in 1:6 c.s mortar in foundation and plinth
[Figure: two rooms 4.5 m × 3.6 m and 4.0 m × 3.6 m with front verandah 1.6 m, 20 × 20 cm pillars, steps 2.4 m wide tread 30 riser 15; door D 1.2 × 2.1 m (frame 10 × 8 cm), window W 1.1 × 1.5 m (frame 10 × 8 cm), shelf S 1.1 × 1.5 m 20 cm deep; walls 30 cm; foundation 90 cm wide with 20 cm layers, 60 cm; 2.5 cm D.P.C.; 15 cm R.C.C. band lintel; AV 10 cm L.C. (2:2:7) over 10 cm RCC slab; wall height 2.7 m, parapet 60 cm. Details approximate.]

## Short answer

Use centre-line method: outer walls 26.00 m, partition shortened at junctions. Excavation 23.47 m³, PCC 1:3:6 5.87 m³, brickwork in foundation and plinth 11.53 m³, including pillar footings and pillars, based on assumed 0.80 m trench depth.

## Answer

#### Reading of the figure
Two rooms 4.5 × 3.6 m and 4.0 × 3.6 m (clear) side by side, 300 mm walls, 1.6 m front verandah on four 20 × 20 cm pillars. Foundation (as marked): 90 cm wide, 20 cm layers; assumed trench depth 0.80 m = PCC 1:3:6 0.20 m + brick step 0.60 m × 0.20 m + wall below GL 0.40 m; plinth 0.45 m above GL; pillar footing 0.90 × 0.90 m.

Outside length = 4.5 + 4.0 + 3 × 0.3 = 9.40 m; depth = 3.6 + 0.6 = 4.2 m. Centre-line of outer walls = 2[(9.40 − 0.3) + (4.2 − 0.3)] = 26.00 m. The partition is 3.6 + 0.3 = 3.90 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 and PCC 3.90 − 0.90 = 3.00 m, brick step 3.90 − 0.60 = 3.30 m, wall 3.90 − 0.30 = 3.60 m.

#### i) Earthwork in excavation
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Wall trench, outer walls, 0.90 × 0.80 deep | 1 | 26.000 | 0.900 | 0.800 | 18.720 |
| Wall trench, partition (3.90 − 0.90) | 1 | 3.000 | 0.900 | 0.800 | 2.160 |
| Pillar pits 0.90 × 0.90 × 0.80 (4 nos.) | 4 | 0.900 | 0.900 | 0.800 | 2.592 |
| **Total** | | | | | **23.472** |

#### ii) PCC (1:3:6) in foundation
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| PCC 1:3:6 under outer walls 0.90 × 0.20 | 1 | 26.000 | 0.900 | 0.200 | 4.680 |
| PCC 1:3:6 under partition | 1 | 3.000 | 0.900 | 0.200 | 0.540 |
| PCC under pillars 0.90 × 0.90 × 0.20 | 4 | 0.900 | 0.900 | 0.200 | 0.648 |
| **Total** | | | | | **5.868** |

#### iii) Brickwork in 1:6 c.s. mortar in foundation and plinth
Wall height above the step = 0.80 − 0.20 − 0.20 + 0.45 = 0.85 m.

| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Brick footing 0.60 × 0.20, outer walls | 1 | 26.000 | 0.600 | 0.200 | 3.120 |
| Brick footing 0.60 × 0.20, partition (3.90 − 0.60) | 1 | 3.300 | 0.600 | 0.200 | 0.396 |
| Wall 0.30 × 0.85 (26.00 + 3.60) | 1 | 29.600 | 0.300 | 0.850 | 7.548 |
| Pillar footing step 0.60 × 0.60 × 0.20 | 4 | 0.600 | 0.600 | 0.200 | 0.288 |
| Pillar 0.23 × 0.23 × (0.80−0.20−0.20+0.45) | 4 | 0.230 | 0.230 | 0.850 | 0.180 |
| **Total** | | | | | **11.532** |

**Answer:** Excavation 23.47 m³; PCC 5.87 m³; brickwork in foundation and plinth 11.53 m³ (assumed details).

## Check yourself

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

1. Total centre-line is 29.60 m = 26.00 m + 3.6 m. Why is the partition taken as the clear length 3.6 m?
   A. It runs between two outer walls, whose thickness is already counted in the outer centre-line
   B. Partitions never have footings
   C. The partition is only 3.6 m because it has a door
   D. Its thickness is subtracted from the plinth
   Answer: A. The partition begins and ends at the centre of the outer walls' overlap; counting the clear length avoids double counting wall thickness. (Key point: Partition length)

2. How many pillar pits are excavated and what is their size?
   A. 4 nos., each 0.90 x 0.90 x 0.80 m
   B. 3 nos., each 0.90 x 0.90 x 0.80 m
   C. 4 nos., each 0.20 x 0.20 x 0.80 m
   D. 1 continuous trench of 0.90 x 0.80 m
   Answer: A. The verandah is carried on four 20 x 20 cm pillars, each with a 0.90 x 0.90 m footing pit, giving 2.592 m3. (Key point: Pillar pits)

3. Trench 0.80 m, PCC 0.20 m, brick step 0.20 m, plinth 0.45 m above GL. What is the wall height?
   A. 1.05 m
   B. 0.85 m
   C. 0.40 m
   D. 1.25 m
   Answer: B. 0.80 - 0.20 - 0.20 = 0.40 m below ground, plus 0.45 m above ground = 0.85 m. (Key point: Wall height above step)

## Related in Estimating and Costing

- [Two-room building: excavation, PCC, brick, plaster](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-h-two-room-fig1) — Estimating and Costing, chapter 6
- [Building: excavation, soling, PCC, brick to plinth](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-o-framed-4-items) — Estimating and Costing, chapter 6
- [Building: excavation, PCC, brick, wood work](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-f-fig3-four-items) — Estimating and Costing, chapter 6
- [Building: excavation, brick, paneled door, plaster](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-p-four-items) — Estimating and Costing, chapter 6
- [Building with verandah: excavation, panelled shutter, brick](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-n-fig3-three-items) — Estimating and Costing, chapter 6
- [Building: excavation, brick 1:4, wood work](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abuilding-k-fig1) — Estimating and Costing, chapter 6

## Related in other subjects

- [Detailed specification of brick work in 1:4 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-brick-1-4) — Construction Management, chapter 12, asked 5×
- [Detailed specification of brick work in 1:6 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-brick-1-6) — Construction Management, chapter 12, asked 5×
- [Brick and mortar: 20 cm wall, 3.4 m](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Awall-eccentric-20cm-100kn-3-4m) — Concrete Technology and Masonry Structure, chapter 8, asked 7×