RADIX Delivers Integrated Ground Screw and Racking Solution for Sloping Agricultural Solar Site

Overview

Full design, supply & installation of 4inL Ground-Mounted solar racking and ground screw foundations for 573kW system

Castle Hill was a repeat project for GW Power, forming the second phase of a ground-mounted solar installation on active agricultural land near Hull. The 573 kW system comprised 1,260 Trina Solar Vertex S+ panels, installed across a field with approximately 3.5 metres of level variation from one end of the site to the other.

Unlike a prepared construction platform, the project had to work with the realities of a farmer’s field. Access was via agricultural tracks, farming operations continued nearby throughout the works, and installation took place during hot, dry conditions with particularly hard ground.

The key challenge was developing a foundation and racking system capable of adapting to the site’s changing levels and geotechnical conditions whilst maintaining a robust and aesthetically pleasing solar array throughout.

Solution

Integrated foundation and racking design for uneven terrain

RADIX developed a combined foundation and racking strategy that allowed the solar array to follow the natural profile of the field without requiring cut-and-fill earthworks or extensive site preparation.

The final solution used:

• 356 fixed-length 76mm × 1,550mm ground screws
• Custom design 4inL Solar Racking

By coordinating the racking lengths, panel layout, field levels, and foundation positions together, RADIX was able to keep each solar rack level while controlling screw projection across the slope. At the lower end of the racks, screw projection was generally maintained between 250–300mm above ground level, avoiding impractical build heights and interface issues.

The system was also engineered to account for uplift loading caused by wind acting on the solar array. T1 pull testing was carried out to verify tensile resistance and support the foundation design.

RADIX completed the ground screw installation in 7 days, with the full racking and solar panel installation completed in 4 weeks, one week ahead of the original programme.

Sustainability & Environmental Benefits:

Lower-impact installation for agricultural land

The Castle Hill project demonstrated how ground screw foundations can reduce disruption on agricultural solar developments while maintaining long-term flexibility.

Compared with excavation-heavy foundation approaches, the RADIX system reduced:

• Cut-and-fill earthworks 
• Excavation and spoil generation 
• Vehicle movements across farmland 
• Ground disturbance and reinstatement requirements 
• Dependency on wet trades and curing periods 

The low-impact installation methodology also supports future reversibility, allowing the land to be reinstated more directly at the end of the project life compared with more permanent foundation systems.