Types of pad foundation
Contents |
[edit] Introduction
Pad foundations are a form of spread foundation formed by rectangular, square, or sometimes circular concrete ‘pads’ that support localised single-point loads such as structural columns, groups of columns or framed structures. This load is then spread by the pad to the bearing layer of soil or rock below. Pad foundations can also be used to support ground beams.
There are several different types of pad foundation:
[edit] Plain concrete
Plain concrete pad foundations that do not use reinforcement are an economical solution but only where the applied load will be relatively light. These can also be referred to as footings. The general rule is that the depth of the pad should be equal to the distance from the face of the vertical element to the edge of the pad on both sides.
[edit] Reinforced concrete
The addition of reinforcement allows for relatively wide but shallow pad foundations. In order to make the reinforcing cage easier to construct and place, the pads tend to be designed as a square plan area. The reinforced concrete base is designed to span in one direction, with the main bars longitudinal in the bottom.
Where the width of the base is restricted or where there is eccentric/inclined loading, rectangular pads can be designed.
[edit] Combined column foundations
These are where two pad foundations are combined into a longer one and can be used where the outer column is close to a site boundary or existing wall. The purpose is that the balancing effect of the internal column can be incorporated. The plan shape is usually a rectangle.
[edit] Continuous pad
This is where the pad foundations are combined together as a single long structural element. This is often the case where the pads and the columns they support are closely spaced. By extending the reinforcement between the pads, differential settlement can be resisted and longitudinal stiffness can be improved.
Foundations that cover the entire footprint of a building are generally referred to as 'raft foundations'.
[edit] Pad and ground beam
This is similar to a continuous pad but differs in that smaller isolated pads are connected by ground beams. This helps to improve structural rigidity.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Future Homes Standard Essentials launched
Future Homes Hub launches new campaign to help the homebuilding sector prepare for the implementation of new building standards.
Building Safety recap February, 2026
Our regular run-down of key building safety related events of the month.
Planning reform: draft NPPF and industry responses.
Last chance to comment on proposed changes to the NPPF.
A Regency palace of colour and sensation. Book review.
Delayed, derailed and devalued
How the UK’s planning crisis is undermining British manufacturing.
How much does it cost to build a house?
A brief run down of key considerations from a London based practice.
The need for a National construction careers campaign
Highlighted by CIOB to cut unemployment, reduce skills gap and deliver on housing and infrastructure ambitions.
AI-Driven automation; reducing time, enhancing compliance
Sustainability; not just compliance but rethinking design, material selection, and the supply chains to support them.
Climate Resilience and Adaptation In the Built Environment
New CIOB Technical Information Sheet by Colin Booth, Professor of Smart and Sustainable Infrastructure.
Turning Enquiries into Profitable Construction Projects
Founder of Develop Coaching and author of Building Your Future; Greg Wilkes shares his insights.
IHBC Signpost: Poetry from concrete
Scotland’s fascinating historic concrete and brutalist architecture with the Engine Shed.
Demonstrating that apprenticeships work for business, people and Scotland’s economy.
Scottish parents prioritise construction and apprenticeships
CIOB data released for Scottish Apprenticeship Week shows construction as top potential career path.
From a Green to a White Paper and the proposal of a General Safety Requirement for construction products.
Creativity, conservation and craft at Barley Studio. Book review.
The challenge as PFI agreements come to an end
How construction deals with inherited assets built under long-term contracts.
Skills plan for engineering and building services
Comprehensive industry report highlights persistent skills challenges across the sector.
Choosing the right design team for a D&B Contract
An architect explains the nature and needs of working within this common procurement route.
Statement from the Interim Chief Construction Advisor
Thouria Istephan; Architect and inquiry panel member outlines ongoing work, priorities and next steps.