BS 5930 and Eurocode 7 lay out the ground investigation framework, but in Sheffield the real value of a grain size analysis lies in distinguishing between the stiff glacial tills that cap the hills and the softer alluvial silts along the Don and Sheaf valleys. The city's post-industrial landscape — where old mill ponds and backfilled quarries sit next to modern student accommodation blocks — demands more than a quick look at a grading curve. Our lab team runs combined sieve and hydrometer tests to BS 1377-2:2022 and BS EN ISO 17892-4, giving engineers the full particle size distribution from coarse gravel down to the clay fraction.
Sheffield spreads across seven hills, and ground conditions change fast between postcodes. We see everything from the sandstone-derived Head deposits in Crookes to the laminated clays near the canal basin. A complete grading analysis reveals drainage potential, frost susceptibility, and compaction behaviour before a single footing is poured, which is why we recommend pairing it with an Atterberg limits assessment when the fines content exceeds 35%.
A grading curve is not just a shape on a chart — in Sheffield's mixed glacial and post-industrial soils it is the first line of defence against fill failure and drainage misdesign.
Local geotechnical context
A contractor we worked with on a basement excavation near the Kelham Island district hit a lens of silty sand that looked clean enough to reuse as engineered fill. Visually it seemed fine. But the hydrometer test showed 28% passing the 63-micron sieve, with a clay fraction that held moisture like a sponge. After the first Sheffield downpour the fill turned to slurry, delaying the project three weeks. This scenario repeats across the city wherever the Pennine Lower Coal Measures weather into fine-grained colluvium.
Without a sieve and hydrometer analysis, the risk of misclassifying a soil is high — and in Sheffield's undulating terrain, that can cascade into retaining wall failures, slope instability, or under-designed drainage blankets. The British Geological Survey maps give a broad indication, but only a lab grading curve confirms whether a soil is suitable for compaction, drainage, or as a concrete aggregate substitute. When the fine fraction matters, a full sedimentation test is not optional.
Questions and answers
How much does a sieve and hydrometer test cost in Sheffield?
A combined grain size analysis with full hydrometer sedimentation typically runs between £70 and £160 per sample, depending on whether organic pre-treatment or wet sieving is required. The exact price depends on the number of samples and turnaround time.
When is a hydrometer test needed instead of just a sieve analysis?
BS 5930 recommends the hydrometer method when more than 10% of the sample passes the 63-micron sieve. In Sheffield's alluvial corridors along the Don Valley, that threshold is exceeded in most samples, making the sedimentation test essential for accurate clay fraction determination.
How long does a full grain size analysis take in the lab?
A standard sieve plus hydrometer test takes 3 to 5 working days from sample receipt. The hydrometer phase alone requires a minimum 24-hour sedimentation period, and we allow extra time for oven-drying and dispersant preparation.
Can you test recycled aggregates from demolition for SHW compliance?
Yes. We run the full SHW Series 600 grading suite on recycled crushed concrete and brick from Sheffield brownfield sites, including the 10% fines value where required. The grading curve is reported alongside the Cu and Cc coefficients for earthworks specification.
