The London clay substrate beneath Romford significantly affects drainage infrastructure, with its expansive properties causing ground movement that can stress and damage underground pipes. During dry periods, clay shrinkage can create voids around pipes, while wet weather causes expansion that can compress and misalign drainage systems. Our engineers account for these geological factors when conducting repairs, using flexible materials and techniques that accommodate natural ground movement. We've observed these patterns across thousands of local jobs, enabling us to predict and prevent common clay-related drainage failures.