---
title: "Building: brick 1:6, ceiling plaster, PCC"
subject: "Estimating and Costing"
chapter: 6
key: "semester_7/estimating_and_costing:building-l-fig1-ceiling-plaster"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/building-l-fig1-ceiling-plaster
site: BCT Engineering
---

# Building: brick 1:6, ceiling plaster, PCC

Estimating and Costing · Chapter 6: Detailed Estimate

- Asked in: 2075 Asoj, 4×3 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/building-l-fig1-ceiling-plaster
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6

## Question

Find the following quantities from the attached building drawing (Fig. 1):
a) Brick work in 1:6 cement sand mortar up to plinth.
b) 10 mm thick cement plastering in ceiling and underside of roof projection.
c) PCC (1:3:6) in foundation.
[Fig. 1: two-room building. Room A 3600 × 4800 mm and Room B 3600 × (about 3000) mm with doors D1, D2 and windows W1, W2 (sizes 1000/1500/1200 mm as marked); external walls 350 mm, partition 230 mm; roof slab with projection; foundation sections for 350 and 230 mm walls with footing, concrete and plinth; floor: 3 mm cement punning 1:4, 40 mm screed 1:4, 75 mm PCC 1:4:8, 150 mm sand filling, earth filling. The scan is rotated and hard to read.]

## Short answer

For L-shaped two-room building: brickwork in 1:6 mortar up to plinth 12.53 m³, 10 mm ceiling and soffit plaster 45.88 m², and PCC (1:3:6) in foundation 3.69 m³.

## Answer

#### Reading of the figure (scan unclear, so assumptions are stated)
Room A is 3.6 × 4.8 m and Room B is 3.6 × 3.0 m (clear). External walls are 350 mm and the partition 230 mm. Overall length = 0.35 + 3.6 + 0.23 + 3.6 + 0.35 = 8.13 m; overall depth = 4.8 + 0.70 = 5.50 m on the Room A side and 3.0 + 0.70 = 3.70 m on the Room B side, so the building is L-shaped. The roof slab follows the building outline with a 0.60 m projection all round (assumed, since the projection is not stated).

Foundation sections (as for the matching drawing): external wall: trench 0.90 m wide × 0.90 m deep, concrete 0.15 m, footings 0.59 × 0.13 m and 0.47 × 0.13 m, then 0.35 m wall; internal wall: trench 0.75 m × 0.75 m, concrete 0.13 m, footings 0.47 × 0.13 and 0.35 × 0.13, then 0.23 m wall; plinth 0.45 m above GL.

Centre-line lengths: external walls = back 7.78 + left 5.15 + right 3.35 + front A 3.775 + front B 3.775 = 23.83 m; partition = 4.80 m. (The small overlaps where the internal-wall foundation meets the external-wall foundation are neglected.)

#### a) Brickwork in 1:6 CM up to plinth
Wall heights: external = 0.90 − 0.15 − 0.13 − 0.13 + 0.45 = 0.94 m; internal = 0.75 − 0.13 − 0.13 − 0.13 + 0.45 = 0.81 m.

| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| Ext. footing 1: 0.59 × 0.13 | 1 | 23.830 | 0.590 | 0.130 | 1.828 |
| Ext. footing 2: 0.47 × 0.13 | 1 | 23.830 | 0.470 | 0.130 | 1.456 |
| Ext. wall 0.35 × 0.94 | 1 | 23.830 | 0.350 | 0.940 | 7.840 |
| Int. footing 1: 0.47 × 0.13 | 1 | 4.800 | 0.470 | 0.130 | 0.293 |
| Int. footing 2: 0.35 × 0.13 | 1 | 4.800 | 0.350 | 0.130 | 0.218 |
| Int. wall 0.23 × 0.81 | 1 | 4.800 | 0.230 | 0.810 | 0.894 |
| **Total** | | | | | **12.530** |

#### b) 10 mm cement plaster in ceiling and underside of roof projection
The projection soffit is a 0.60 m strip along the outer perimeter plus the corner squares. For an L-shaped plan the perimeter equals that of the enclosing rectangle, 2(8.13 + 5.50) = 27.26 m, and the net number of corner squares is 4.

| Item | No. | L (m) | B (m) | H/D (m) | Qty (m²) |
|---|---|---|---|---|---|
| Room A ceiling 3.6 × 4.8 | 1 | 3.600 | 4.800 | – | 17.280 |
| Room B ceiling 3.6 × 3.0 | 1 | 3.600 | 3.000 | – | 10.800 |
| Projection soffit: 27.26 × 0.60 | 1 | 27.260 | 0.600 | – | 16.356 |
| Projection corners 0.60 × 0.60 | 4 | 0.600 | 0.600 | – | 1.440 |
| **Total** | | | | | **45.876** |

#### c) PCC (1:3:6) in foundation
| Item | No. | L (m) | B (m) | H/D (m) | Qty (m³) |
|---|---|---|---|---|---|
| PCC external walls (0.90 wide × 0.15) | 1 | 23.830 | 0.900 | 0.150 | 3.217 |
| PCC internal wall (0.75 wide × 0.13) | 1 | 4.800 | 0.750 | 0.130 | 0.468 |
| **Total** | | | | | **3.685** |

**Answer:** Brickwork to plinth 12.53 m³; ceiling and projection soffit plaster 45.88 m²; foundation PCC 3.69 m³ (assumed details).

## Check yourself

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

1. For the external wall (trench 0.90 m, concrete 0.15 m, two footings of 0.13 m each, plinth 0.45 m), what is the wall height used?
   A. 0.49 m
   B. 0.94 m
   C. 1.39 m
   D. 0.81 m
   Answer: B. 0.90 - 0.15 - 0.13 - 0.13 = 0.49 m, plus 0.45 m plinth above GL = 0.94 m. (Key point: Wall height to plinth)

2. Why are the internal wall height (0.81 m) and external wall height (0.94 m) different?
   A. The internal wall has a shallower trench (0.75 m) and thinner layers, so less depth remains above the footings
   B. The internal wall has a lower plinth
   C. The internal wall is plastered
   D. The internal wall omits its footings
   Answer: A. Height depends on trench depth and layer thicknesses; with a 0.75 m trench the result is 0.75 - 0.13 - 0.13 - 0.13 + 0.45 = 0.81 m. (Key point: Different heights)

3. What is included in the brickwork up to plinth total of 12.53 m3?
   A. Only the walls above ground
   B. Only the footings, not the wall
   C. Footings, wall and the PCC bed
   D. Both brick footing steps and the wall up to plinth for external and internal walls
   Answer: D. Brickwork up to plinth includes each wall's brick footings and the wall to plinth; PCC is measured under its own item. (Key point: Brickwork up to plinth contents)

4. Why is the slab rectangle taken as (8.13 + 1.2) x (5.50 + 1.2) when computing the soffit?
   A. The 0.60 m roof projection is added on both sides of each dimension
   B. Plaster thickness is added to each side
   C. Walls are 0.60 m thick
   D. The projection is added only on the front
   Answer: A. A projection of 0.60 m all round adds 2 x 0.60 = 1.2 m to both length and width; the room ceilings and walls are then subtracted to get the outside soffit. (Key point: Soffit plaster size)

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