The British Standard BS 5930:2015+A1:2020 remains the backbone of site investigation practice across the UK, and nowhere is its application more critical than on the variable Quaternary deposits underlying Ipswich. From the chalky till of the Lowestoft Formation to the alluvial silts flanking the River Orwell, a solid grain size analysis determines whether a soil can support a shallow foundation, serve as engineered fill, or requires replacement. Our laboratory combines dry sieving for the coarse fraction (retained on the 63 μm sieve) with the sedimentation hydrometer method for silts and clays, producing a full particle size distribution curve that feeds directly into the Atterberg limits assessment needed for plasticity classification under the Unified Soil Classification System. For contractors working on the Ipswich Northern Route improvements or residential schemes in the Priory Heath area, getting the grading right before the first lorry of imported fill arrives saves weeks of delay.
A grain size curve is not just a lab report — it is the first honest conversation you have with the ground about what it can and cannot carry.
