Screw piles are high-grade steel shafts. Depending on the usage and ground conditions, they have a single or multiple helix to assist in penetrating the soil. The foundation piling is screwed into the earth by a hydraulic motor, until the specified load-bearing pressure for the structure is met.

When screwed into the ground, screw piles essentially cut into the soil in a constant pitch, rather than just auguring through it. The helical shafts and flights are usually manufactured in a particular way to suit specific ground conditions. When the piles reach the intended depth, they remain permanently secured in place, and the gaps are typically filled with concrete. The part left protruding on the ground provides a powerful reinforcement, where the building structure can be connected, or in some cases increase the capacity of the piles.

In comparison to a standard concrete foundation, installing screw piles takes significantly less time. It utilises less machinery, therefore becoming increasingly cost efficient. Depending on the size of the pile, a wide range of plant sizes can be used for the installation, including hand held machines. In most cases, only one machine will be required when installing a steel screw pile foundation. 

Screwed piling is typically installed using a hydraulic torque drive. In order to secure a screw pile into the ground, powerful hydraulic motors are used, since they have the capacity to apply the large torques required for the installation. Typically, these motors are fastened into the handling machines, which usually come in a wide range of sizes, from 0.5T Bobcats and 20T Excavators, up to 100T crane rigs (mast mounted).

Necessary handling machines and hydraulic motors required are typically determined by:

• • Torsional capacity of shaft
  • Positional tolerances
  • Minimum torque requirements for the installation
  • Site ground and soil profile conditions
  • Site access limitations

One of the most important parts of the design is the interface between the pile and the building, as it requires the utmost care. The connection is ideally designed and constructed while considering the building and the soil/ground conditions where the piles are to be screwed. This process will require a geo-technical analysis, as well as structural input from a professional. 

Casting the head of screw piles into the concrete foundation of the building is the most common way of connecting a screw pile into the foundation of a structure. Rigidity is achieved by casting steel reinforcement bars into the piles, and protruding them out into the building’s footing. The reinforcing bars are generally bent at 90 degrees, and this can sometimes be substituted with Reidbar reinforcement (footplates or flange nuts screwed into the ends).

All steel will eventually corrode at some point. However, most designs take this into consideration, all high quality piles will perform for their entire lifetime. To address corrosion, consider the following:

• • Surface protection should be applied onto the steel in order to limit the rate of corrosion
  • Remember to allow for some sacrificial corrosion, which is the predetermined rate of corrosion in line with the accepted standards.

Managing loads of up to 100 tonne or 1000kN our screw piles are designed, manufactured and installed to effectively transfer building loads via the shaft to the helix, located at the bottom of the shaft. With high bearing and tension capacity that exceeds requirements, they are suitable for a wide range of installations; including sails, signs and wind-prone buildings.

Our unique screw pile system can reach depths of 48 metres and with low head-room clearance they are ideal for underpinning internal and under building jobs.

Installed many times faster than driven piles and suitable for all soil types, screw piles offer a cost effective and time saving solution to meet your project requirements. Vibration free and environmentally friendly, they gain further efficiency savings by making low noise and producing no spoil.