Benching vs. Underpinning: Understanding The Key Differences


When it comes to strengthening or stabilizing the foundations of buildings or structures, two commonly used methods are benching and underpinning. While both techniques serve the vital purpose of enhancing structural integrity, they differ significantly in their approaches and applications. In this article, we’ll explore these methods, highlighting their key differences to help you make informed decisions for your foundation-related projects.

What is Benching?

Benching, also known as bench footing, is a foundation enhancement technique that involves excavating the soil beneath an existing foundation and extending it horizontally. This process creates wider and more stable footing for the foundation walls. Benching is typically chosen when the existing foundation shows signs of settling or instability but doesn’t require extensive structural changes.

What is Underpinning?

Underpinning, on the other hand, is a more complex and specialized method. It involves strengthening or extending the foundation’s depth by installing new structural supports beneath it. This is achieved by digging individual pits or trenches beneath the existing foundation (footings) and then pouring concrete or inserting structural supports (jacks or heli-copiers) to reinforce it. Underpinning is also often employed when the foundation faces serious issues, such as sinking, cracking, or uneven settlement.

Purpose and Scope

The primary difference between benching and underpinning lies in their purpose and scope. Benching is typically a preventive or corrective measure to enhance stability, while underpinning is a comprehensive solution to address severe foundation issues. Underpinning can also be used to increase the depth of a foundation to support additional floors or heavier loads.

Complexity and Cost

In terms of complexity and cost, benching is generally a less intricate and more cost-effective solution. It requires less equipment and labour compared to underpinning, making it a suitable choice for less severe foundation concerns. On the other hand, underpinning, being a more involved process, is associated with higher costs due to the need for specialised equipment and skilled professionals.

Benching vs. Underpinning

When deciding between benching and underpinning for your foundation-related project, consider the severity of the foundation issues, the project budget, and the long-term goals. Benching is a practical option for minor stability improvements, while underpinning is the go-to choice for addressing significant foundation problems and supporting larger structural modifications.

Consulting with experienced substructure professionals is crucial to determine the most suitable method.


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