Cheltenham’s geology shifts dramatically within a few hundred metres — from the oolitic limestone of the Cotswold escarpment to the soft alluvial clays and river terrace gravels of the Severn Vale. That contrast means a pile foundation design that works near Leckhampton Hill will not suit a site down by the River Chelt without substantial re-evaluation. In our laboratory, we see this every week: cores from the upper slopes show competent Inferior Oolite, while samples taken barely a mile north reveal compressible silts that demand a completely different load-transfer strategy. Before a single pile is sized, we subject the ground to a full characterisation programme, integrating borehole logging with advanced lab testing under BS EN 1997-1:2004 and the procedural rigour of BS 5930. When the stratigraphy is uncertain, we often recommend a CPT test to capture continuous resistance profiles, which helps us define pile bearing layers without the disturbance that sampling can introduce.
A pile is only as reliable as the ground model behind it — in Cheltenham’s mixed geology, skipping the lab stage is a risk no sensible design should carry.
