---
title: "Double and cantilever scaffolding"
subject: "Building Technology"
chapter: 8
key: "semester_6/building_technology:scaffold-double-cantilever"
source: https://www.bctengineer.com/q/semester_6/building_technology/scaffold-double-cantilever
site: BCT Engineering
---

# Double and cantilever scaffolding

Building Technology · Chapter 8: Temporary construction

- Asked in: 2080 Chaitra, 6 marks
- Video: [Types of Scaffolding Explained: Single, Double, Cantilever & More for Civil Engineers | Mohan Dangi](https://www.youtube.com/watch?v=37kE5_SaG7g) — Digitech education
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/scaffold-double-cantilever
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-8

## Question

Describe double scaffolding and cantilever scaffolding (specify uses) with properly labelled sketch.

## Short answer

Double scaffolding uses two rows of standards, with putlogs resting on both ledgers, not entering the wall; it is used for stone masonry. Cantilever scaffolding supports its platform on needles projecting from the wall, and is used where ground support is impossible or in streets.

## Answer

#### Double scaffolding
This is also called a mason's scaffold. Two rows of standards are put up, the first close to the wall (about 20-30 cm) and the second at 1.2-1.5 m from it. **Ledgers** join the standards, **putlogs** rest on both rows of ledgers (not in the wall), and **braces** make the frame rigid. It is used for stone masonry and heavy work where holes in the wall are not allowed.

```text
  wall |std  ledger  std
  wall |  |=putlog====|
  wall |  |  boards   |
  wall |  | /brace    |
  wall |__|/__________|__ sole plate
```
**Use:** stone masonry, tall buildings, heavy work.

#### Cantilever scaffolding
**Cantilever scaffolding** is a scaffold in which the platform is carried on **needles** (projecting beams) that cantilever out from the wall, instead of on standards resting on the ground. It is used when the ground cannot support standards (e.g. beside a basement, or on soft or sloping ground), or when the building is on a street where the pavement must remain free.

**Parts:** needles (steel/timber beams), struts or braces, standards on the needles, ledgers, putlogs, boards and guard rails.

**Types:**
1. *Needle (built-up) type:* needles pass through holes in the wall and are anchored inside by a counterweight or by tying to the floor.
2. *Truss-out type:* needles are supported by inclined struts fixed to the wall.

```text
              guard rail |
    wall |== boards ======|
    wall |==== needle ====|
    wall |           /
    wall |         /
    wall |       /  strut
    wall |     /
    wall |   /
    wall | /
```
**Use:** where the ground cannot support standards, or in busy streets.

## Check yourself

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

1. In a double scaffold, the putlogs rest on:
   A. Roof
   B. Wall only
   C. Ground
   D. Both rows of standards' ledgers, not in the wall
   Answer: D. Putlogs rest on both ledgers. (Key point: Double scaffold)

2. Cantilever scaffold is used when:
   A. Painting a roof
   B. Ground is perfect
   C. Ground cannot support standards or the pavement must stay free
   D. Trench is dug
   Answer: C. Needles carry the platform instead of ground-based standards. (Key point: Cantilever use)

3. A truss-out type cantilever scaffold has needles:
   A. Anchored by counterweight
   B. Supported by inclined struts fixed to the wall
   C. Held by ropes
   D. Standing on ground
   Answer: B. Truss-out type uses inclined struts; needle type uses anchoring inside. (Key point: Cantilever types)

## 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
- [Why temporary construction; single and double scaffolding](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Ascaffolding-single-double) — Building Technology, chapter 8

## Related in other subjects

- [Cantilever deflection by integration and superposition](https://www.bctengineer.com/question.md?key=semester_4%2Fstrength_of_materials_mechanical%3Acantilever-udl-point-load-deflection) — Strength of Materials, chapter 7
- [Propped cantilever with UDL by integration](https://www.bctengineer.com/question.md?key=semester_4%2Fstrength_of_materials_mechanical%3Apropped-cantilever-udl-prop-reaction) — Strength of Materials, chapter 7