Drive from the maritime alluvium around SA1 down to the sandstone ridge of Townhill and you feel the difference underfoot before you see it in a borehole log. Swansea's ground profile switches from compressible estuarine clays near the Tawe to stiff glacial till and weathered Coal Measures within half a mile, which means a pad-and-strip approach that works in Sketty can become a settlement risk down by the marina. For schemes on these transitional soils, raft foundation design often provides the most rational load-spreading solution, bridging localised soft spots without resorting to deep piles on every grid line. Our team works directly with ground investigation data from CPT testing and trial pits to calibrate the modulus of subgrade reaction across the footprint, not just from a textbook table, so the mat thickness and reinforcement reflect what the ground actually offers rather than a conservative assumption that drives up concrete volume.
A raft on Swansea's glacial till is rarely a textbook rigid slab; it's a tuned plate matching stiffness to the buried channel geometry beneath the footprint.
