---
title: "Setting out of a building"
subject: "Building Technology"
chapter: 2
key: "semester_6/building_technology:setting-out-building"
source: https://www.bctengineer.com/q/semester_6/building_technology/setting-out-building
site: BCT Engineering
---

# Setting out of a building

Building Technology · Chapter 2: Foundations

- Asked in: 2072 Asoj, 8 marks
- Video: [Building SETTING OUT Using Builder's SQUARE |3-4-5 METHOD](https://www.youtube.com/watch?v=wx_f-v_Gag0) — KEKS CONSTRUCTION ENGINEERING and GREYTEST DESIGN CONSULT
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/setting-out-building
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-2

## Question

Explain with neat sketches the method of setting out of a building.

## Short answer

Setting out transfers the building plan to the ground. Fix a base line, mark corners with the 3-4-5 right-angle method, check diagonals, mark wall lines with lime, and fix profile boards outside the excavation to preserve the centre lines and levels during construction.

## Answer

**Setting out** is the process of transferring the dimensions and positions of the building from the drawing to the ground, so that excavation and construction follow the plan exactly.

#### Procedure (for a building with walls)
1. **Site clearing and base line**: Clear the site. Fix a base line parallel to the road or to a reference line from the plan (a permanent line, set back as per the bye-laws). Fix a benchmark for levels.
2. **Marking the first corner**: Fix a peg at one corner of the building at the given distance from the base line.
3. **Right angle**: Set a right angle with the **3-4-5 method** (a triangle with sides of 3 m, 4 m and 5 m), or with a theodolite or a box square, to mark the adjacent wall line.
4. **Other corners**: Measure the length and breadth with a tape, fix pegs at all corners, and check that the diagonals are equal in length (as they must be for a rectangle).
5. **Marking the wall lines**: Join the corner pegs with string, and mark the centre lines and the trench width with lime powder.
6. **Profile boards (batter boards)**: Fix boards on wooden posts 1.5 to 2 m outside each corner, outside the area of excavation. Wires or nails on the boards mark the centre lines and the widths of the trench and the footing. These stay in place during excavation.
7. **Levels**: Mark the depth of excavation with a level and boning rods, or with a cut line at the required depth.
8. **Checking**: Check lengths, diagonals and levels before the excavation starts.

```text
    P1----------------P2     P = profile boards
     |    +--------+  |      
     |    | trench |  |      Check: both diagonals equal
     |    +--------+  |
    P4----------------P3
         3-4-5 triangle for right angle
```
For a framed building, the column centres are fixed by a grid of centre lines laid out by tape or total station, and marked on the profile boards.

## Check yourself

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

1. Setting out means:
   A. Measuring quantities
   B. Transferring dimensions and positions from the drawing to the ground
   C. Digging a well
   D. Painting the building
   Answer: B. It ensures excavation and construction follow the plan. (Key point: Definition)

2. The 3-4-5 method is used to:
   A. Check cement
   B. Fix a benchmark
   C. Set a right angle
   D. Measure levels
   Answer: C. A triangle with sides 3, 4 and 5 m has a right angle. (Key point: 3-4-5 method)

3. A rectangle's corners are correct if:
   A. Diagonals differ by 1 m
   B. Diagonals are equal
   C. Sides are unequal
   D. Pegs are in a line
   Answer: B. Equal diagonals confirm a true rectangle. (Key point: Diagonal check)

4. Profile boards are fixed:
   A. Never
   B. Outside the excavation area at corners
   C. On the roof
   D. Inside the trench
   Answer: B. They stay in place during excavation, marking centre lines and widths. (Key point: Profile boards)

## Related in Building Technology

- [Cantilever scaffolding with sketches](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Acantilever-scaffolding-sketch) — Building Technology, chapter 8
- [Flying shoring with neat sketches](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aflying-shoring-sketch) — Building Technology, chapter 8
- [Principles of laying out water supply system](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Awater-supply-principles) — Building Technology, chapter 12
- [Passive solar design and building layout](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apassive-solar-design) — Building Technology, chapter 1
- [Building and its types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Abuilding-types-sketches) — Building Technology, chapter 1
- [Shoring types and flying shore](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Ashoring-flying) — Building Technology, chapter 8, asked 2×

## Related in other subjects

- [Short note: Setting out vertical curve](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Avertical-curve-setting-out-note) — Surveying II, chapter 6
- [Setting out right hand side composite curve](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aright-hand-composite-curve-setting-out) — Surveying II, chapter 6
- [Setting out simple curve by Rankine's method](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Asimple-curve-rankine-method-sketch) — Surveying II, chapter 6
- [Short note: Rankine's method of curve setting](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Arankine-method-circular-curve) — Surveying II, chapter 6