That’s why contractors, developers, and homeowners across the UK rely on Cotterill’s Drainage for high-quality interlocking geo grids backed by expert advice and outstanding service. What Are Interlocking Geo Grids? Interlocking geo grids are modular, honeycomb-like structures manufactured from durable, lightweight plastics. Why Interlocking Geo Grids Are ImportantLoad Distribution By spreading the weight of vehicles or foot traffic, geo grids prevent rutting and sinking on softer ground. For contractors, developers, and homeowners alike, buying interlocking geo grids from Cotterill’s means confidence, reliability, and long-term performance.