Screw piles have gained widespread recognition as a reliable and efficient foundation solution for a variety of construction projects. These innovative devices offer several advantages over traditional foundation methods, such as reduced installation time, minimal environmental impact, and cost-effectiveness. However, their successful implementation relies heavily on the understanding and utilisation of capacity charts. In this article, we will explore the crucial role of capacity charts when using screw piles and how they ensure the stability and safety of structures.

Understanding Screw Piles

Screw piles, also known as helical piles or screw anchors, are cylindrical steel shafts featuring helical plates, similar to large screws. These plates provide anchorage by turning the pile into the ground, utilizing the soil’s bearing capacity to support the load above. They can be installed using various techniques, such as traditional excavators, skid-steer loaders, or specialized machinery.

Importance of Capacity Charts

Capacity charts are fundamental tools that provide engineers, contractors, and construction professionals with essential data for designing and installing screw piles. These charts contain vital information related to the load-bearing capacity of different screw pile configurations based on factors such as soil type, pile size, helix dimensions, installation depth, and site-specific conditions.

  • Ensuring Structural Integrity

One of the primary functions of capacity charts is to guarantee the structural integrity of the foundation. By consulting the chart, engineers can determine the appropriate pile size and helix configuration required to support the intended load. The chart considers variables like soil properties and environmental conditions to ensure the pile’s capacity matches the demands of the structure. Without adhering to these guidelines, the foundation may fail to provide sufficient support, leading to structural damage or even collapse.

  • 2. Site-Specific Adaptability

Every construction site is unique, with distinct soil conditions and load requirements. Capacity charts empower engineers to customize screw pile installations based on these site-specific factors (see our case studies). By analysing the data on the chart, they can adjust the pile dimensions, helix spacing, or shaft material to optimize the load-bearing capacity while avoiding potential risks.

  • Safety and Risk Mitigation

The use of capacity charts reduces the risk of overloading or underestimating the screw pile’s capacity. Overloading can lead to catastrophic failures, while underestimating the capacity may result in oversized piles, increasing construction costs unnecessarily. Capacity charts serve as a safety net, helping professionals make informed decisions and minimizing potential risks associated with foundation failure.

  • Compliance and Regulation

In the construction industry, adherence to regulations and building codes is crucial to ensure public safety and the longevity of structures. Capacity charts are developed in compliance with engineering standards and guidelines set forth by regulatory authorities. By following the recommendations outlined in these charts, contractors can demonstrate due diligence and compliance, thereby avoiding legal complications and liabilities.


The importance of capacity charts when using screw piles cannot be overstated. They serve as indispensable tools for designing and implementing reliable foundations that meet safety standards and comply with regulations. Capacity charts enable engineers and contractors to accurately assess the load-bearing capacity of screw piles based on soil conditions and site-specific factors, ensuring structural integrity and safety throughout the construction process. By embracing the data-driven approach offered by capacity charts, the construction industry can continue to benefit from the efficiency and effectiveness of screw pile foundations.


Hand held equipment being used outside house for screw piles
Square Shaft Helical Piles Capacity Chart
Installing steel base using screw piles

For further information on Ground Sun’s Helical Screw Piling & Underpinning,
contact us on 0208 989 7312.