---
title: "Two-room building: brick plinth, door shutters, plaster"
subject: "Estimating and Costing"
chapter: 6
key: "semester_7/estimating_and_costing:building-m-two-room-three-items"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/building-m-two-room-three-items
site: BCT Engineering
---

# Two-room building: brick plinth, door shutters, plaster

Estimating and Costing · Chapter 6: Detailed Estimate

- Asked in: 2074 Chaitra, 10+5+5 marks
- Video: [Estimation of One Room - 2023 || Long wall and Short wall method || @CivilConceptandPlans](https://www.youtube.com/watch?v=bqrq47VnFaE) — Civil Concept and Plans
- 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-m-two-room-three-items
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-6

## Question

A drawing of a building is attached herewith. Calculate the quantities of:
i) Brickwork in cement mortar (1:6) up to plinth
ii) 35 mm thick paneled door shutters.
iii) 10 mm thick cement plaster in ceilings and underside of roof projection.
[Two Room Building: all dimensions in mm, assume necessary dimensions. Plan: room A 3600 × 4800 and room B 3600 × 5500; external walls 350 mm, internal wall 230 mm; bay dimensions 1550, 1200, 2630, 1200, 1550 and 2000, 1500, 2000; front 1050, 1000, 700, 2630, 700, 1000, 1050. Foundation — external wall: depth 900, width 900, concrete depth 150; footings width and depth: 1st 590 and 130, 2nd 470 and 130, 3rd footing and plinth 350 thick; plinth height 450; sill height 750. Internal wall: depth 750, width 750, concrete depth 130; footings: 1st 470 and 130, 2nd 350 and 130, 3rd footing and plinth 230; plinth height 450; sill height 750. Steps: tread 300, riser 150, 100 th PCC. Roofs: RCC slab thickness 100, projection 600, parapet wall 110 thick, 300 high at the end of roof projection. Superstructure: floor to floor height 2700, external wall 350, internal wall 230. Openings: doors D 1200 × 2100, windows W1 1000 × 1000, W2 1200 × 1200, W3 1200 × 1200; frame size 75 × 100; doors and windows shutter 35 thick.]

## Short answer

Brickwork in 1:6 cement mortar up to plinth: 13.90 m3. Door shutters (35 mm, 3 nos.) after frame deduction: 6.38 m2. Ceiling plaster and roof projection soffit: 55.72 m2.

## Answer

#### Reading of the data
Along the front: 350 + 3600 + 230 + 3600 + 350 = 8130 mm (matches 1550 + 1200 + 2630 + 1200 + 1550 = 8130). Room A is 3.6 × 4.8 m, Room B 3.6 × 5.5 m, so the outer depth is 4.8 + 0.70 = 5.50 m on the Room A side and 5.5 + 0.70 = 6.20 m on the Room B side (an L-shaped plan). External walls 350 mm, internal 230 mm. Slab 100 mm with 600 mm projection, parapet 110 × 300 mm on the projection edge. The number of openings is not given, so **3 doors D (1.2 × 2.1 m)** are assumed (two external, one in the partition); the windows are not needed for this question.

Foundation from the given data: external wall trench 900 wide × 900 deep, concrete 150 mm, footings 590 × 130 and 470 × 130, 350 mm wall to plinth (450 mm); internal wall trench 750 × 750, concrete 130 mm, footings 470 × 130 and 350 × 130, 230 mm wall to plinth.

Centre-line lengths: external walls = back 7.78 + left 5.15 + right 5.85 + fronts 7.55 = 26.33 m; partition (full depth of Room B) = 5.50 m. (The small overlaps where the internal-wall footings meet the external-wall footings are neglected.)

#### i) Brickwork in cement mortar 1:6 up to plinth
External wall height = 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 | 26.330 | 0.590 | 0.130 | 2.020 |
| Ext. footing 2: 0.47 × 0.13 | 1 | 26.330 | 0.470 | 0.130 | 1.609 |
| Ext. wall 0.35 × 0.94 | 1 | 26.330 | 0.350 | 0.940 | 8.663 |
| Int. footing 1: 0.47 × 0.13 | 1 | 5.500 | 0.470 | 0.130 | 0.336 |
| Int. footing 2: 0.35 × 0.13 | 1 | 5.500 | 0.350 | 0.130 | 0.250 |
| Int. wall 0.23 × 0.81 | 1 | 5.500 | 0.230 | 0.810 | 1.025 |
| **Total** | | | | | **13.902** |

#### ii) 35 mm thick panelled door shutters
The frame is 75 × 100 mm, so each shutter is smaller than the 1.2 × 2.1 m opening by 75 mm at each vertical side and at the head.

| Item | No. | L (m) | B (m) | H/D (m) | Qty (m²) |
|---|---|---|---|---|---|
| Panelled shutter D 1.2×2.1 less frame (1.05 × 2.025), 3 nos. | 3 | 1.050 | 2.025 | – | 6.379 |
| **Total** | | | | | **6.379** |

#### iii) 10 mm plaster in ceilings and underside of roof projection
The slab follows the L-shaped outline with a 0.60 m projection. The soffit outside the walls is a 0.60 m strip along the perimeter, 2(8.13 + 6.20) = 28.66 m (the same as the enclosing rectangle for an L-shape), plus 4 net corner squares of 0.60 × 0.60 m.

| 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 × 5.5 | 1 | 3.600 | 5.500 | – | 19.800 |
| Projection soffit: 28.66 × 0.60 | 1 | 28.660 | 0.600 | – | 17.196 |
| Projection corners 0.60 × 0.60 | 4 | 0.600 | 0.600 | – | 1.440 |
| **Total** | | | | | **55.716** |

**Answer:** Brickwork to plinth 13.90 m³; door shutters 6.38 m² (3 doors); ceiling and projection soffit plaster 55.72 m².

## Check yourself

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

1. Opening is 1.2 x 2.1 m with a 75 mm frame. How are the shutter dimensions found?
   A. 1.2 - 0.075 = 1.125 m wide and 2.1 - 2 x 0.075 = 1.95 m high
   B. 1.2 - 2 x 0.075 = 1.05 m wide and 2.1 - 0.075 = 2.025 m high
   C. 1.2 x 2.1 m, the full opening size
   D. 1.2 - 0.15 = 1.05 m wide and 2.1 - 0.15 = 1.95 m high
   Answer: B. The frame occupies the two sides and the head, but a door has no sill, so only one frame width is taken off the height. (Key point: Shutter size from opening)

2. What is the external wall height used for brickwork to plinth (trench 0.90, concrete 0.15, two footings 0.13 each, plinth 0.45)?
   A. 0.49 m
   B. 0.81 m
   C. 0.94 m
   D. 1.39 m
   Answer: C. 0.90 - 0.15 - 0.13 - 0.13 + 0.45 = 0.94 m. (Key point: External wall height)

3. Why is the slab size 9.33 x 7.40 m when the building is 8.13 m wide?
   A. A 600 mm projection is added on both sides (8.13 + 1.2 = 9.33)
   B. The parapet adds 0.60 m
   C. Wall thicknesses are added twice
   D. Plaster thickness is added to the length
   Answer: A. The roof slab extends 0.60 m beyond the walls on each side, and similarly in the other direction. (Key point: Projection in slab size)

4. How is the back wall centre-line 7.78 m obtained for an overall length of 8.13 m with 350 mm walls?
   A. 8.13 - 0.70
   B. 8.13 - 0.35, because half the wall thickness is deducted at each end
   C. 8.13 - 0.175
   D. 8.13 + 0.35
   Answer: B. Centre-line length is the overall length minus one wall thickness: 8.13 - 0.35 = 7.78 m. (Key point: Back wall centre-line)

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