---
title: "Definition of underpinning"
subject: "Building Technology"
chapter: 8
key: "semester_6/building_technology:define-underpinning-term"
source: https://www.bctengineer.com/q/semester_6/building_technology/define-underpinning-term
site: BCT Engineering
---

# Definition of underpinning

Building Technology · Chapter 8: Temporary construction

- Asked in: 2079 Asoj, 1 marks; 2076 Bhadra, 2 marks (asked 2 times)
- Video: [What is Underpinning the Foundation? | Underpinning Methods](https://www.youtube.com/watch?v=gd3ktWm8Ojw) — Gurukul of Civil Engineers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_6/building_technology/define-underpinning-term
- Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-8

## Question

Define underpinning.

## Short answer

Underpinning is the process of strengthening or deepening an existing building's foundation by extending it to a firmer stratum or enlarging its base to safely carry loads. It involves excavating below the old foundation in sections and constructing new concrete or masonry up to the old footing, transferring loads deeper.

## Answer

**Underpinning** is the process of strengthening or deepening the foundation of an existing building by extending it to a firmer or deeper stratum, or enlarging the base, so that it can carry the load safely.

It is carried out by digging below the old foundation in short sections and building new concrete or masonry up to the base of the old footing, so that the load is shifted to a deeper or firmer stratum.

## Check yourself

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

1. Underpinning strengthens an existing building by:
   A. Adding paint
   B. Strengthening or deepening the foundation to a firmer or deeper stratum
   C. Removing the walls
   D. Adding a roof
   Answer: B. It extends the foundation to firmer or deeper ground, or enlarges the base. (Key point: Definition)

2. How is underpinning carried out in short?
   A. Drive timber boards beside the wall
   B. Dig below the old foundation in short sections and build new concrete or masonry up to the base of the old footing
   C. Raise the wall height
   D. Fill the room with sand
   Answer: B. New work built in sections shifts the load to a deeper or firmer stratum. (Key point: How it is carried out)

3. What is the aim of underpinning?
   A. To change its colour
   B. To make the building lighter
   C. To let the building carry its load safely
   D. To make it temporary
   Answer: C. The foundation is improved so that the building can carry its load safely. (Key point: Purpose)