---
title: "Short note: Formwork"
subject: "Building Technology"
chapter: 8
key: "semester_6/building_technology:short-formwork"
source: https://www.bctengineer.com/q/semester_6/building_technology/short-formwork
site: BCT Engineering
---

# Short note: Formwork

Building Technology · Chapter 8: Temporary construction

- Asked in: 2074 Bhadra, 4 marks
- Video: [Formwork for construction](https://www.youtube.com/watch?v=32Gu28vstMI) — Environmental Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/short-formwork
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-8

## Question

Write a short note on form works.

## Short answer

Formwork is a temporary mould of timber, plywood, steel or aluminium into which fresh concrete is placed to obtain the required shape. It must be strong, rigid, leak-proof, easy to strip and re-use, with smooth oiled surfaces. Stripping times per IS 456: vertical sides 16-24 hours, slab soffits 3 days, beam soffits 7 days.

## Answer

**Formwork** (shuttering or centering) is a temporary mould, made of timber, plywood, steel or aluminium, into which fresh concrete is placed to get the required shape. It stays in place until the concrete gains enough strength.

#### Requirements
- Strong enough to carry the weight of wet concrete, workers and vibration.
- Rigid and stable, with little deflection.
- Tight joints, to stop leakage of cement slurry.
- Easy to erect, strip and re-use.
- Smooth inner surface, treated with mould oil.
- Economical and accurate in dimensions.

#### Types by material
Timber, plywood, steel, aluminium, plastic and fibreglass.

#### Components
Sheathing, studs/joists, walings, props, braces, ties, sole plates and wedges.

#### Stripping time (IS 456, OPC)
Vertical faces: 16-24 hours; slab soffits: 3 days (props refixed); beam soffits: 7 days (props refixed); props to slabs: 7 days up to 4.5 m span, 14 days over 4.5 m; props to beams: 14 days up to 6 m span, 21 days over 6 m.

## Check yourself

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

1. Formwork is:
   A. A permanent wall
   B. A temporary mould into which fresh concrete is placed to get the required shape
   C. A type of cement
   D. A finishing layer
   Answer: B. Formwork stays until concrete gains enough strength. (Key point: Definition)

2. Why must formwork joints be tight?
   A. To make it lighter
   B. To stop leakage of cement slurry
   C. To allow ventilation
   D. To reduce cost
   Answer: B. Tight joints prevent loss of cement grout. (Key point: Requirements)

3. Stripping time for vertical sides (IS 456) is:
   A. 7 days
   B. 16-24 hours
   C. 14 days
   D. 28 days
   Answer: B. Vertical sides are struck after 16-24 hours; soffit props remain longer. (Key point: Stripping time)

## Related in other subjects

- [Units: iron grills, skirting, formwork, shutters](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aunits-grills-skirting-formwork-shutters) — Estimating and Costing, chapter 1
- [Bill of quantities for RCC T-beam bridge](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aboq-rcc-t-beam-decking) — Estimating and Costing, chapter 2