Grain Size Analysis (Sieve + Hydrometer) for Geotechnical Projects in St. Catharines

The Niagara Escarpment shapes more than the region's skyline—it defines the subsurface conditions that challenge every foundation in St. Catharines. Glacial till, lacustrine silts, and shale fragments create soil profiles that demand precise particle size characterization before any structural load is applied. A complete grain size analysis using mechanical sieves plus hydrometer sedimentation provides the full gradation curve, from coarse gravel down to colloidal clay. Without this data, drainage design and frost protection decisions in St. Catharines become guesswork. Our team runs the combined ASTM D422 and ASTM D7928 procedures on samples extracted from test pits and boreholes throughout the city, delivering results that feed directly into NBCC compliance and CSA A23.3 concrete exposure class selection. When your site sits on the silty clays common near the Twelve Mile Creek floodplain, the hydrometer fraction often reveals a plasticity risk that sieve-only reports miss entirely.

The hydrometer reading at 24 hours tells you more about frost heave potential than the entire sieve stack combined.

Our service areas

Our approach and scope

St. Catharines sits between two Great Lakes, where winter frost penetrates well beyond 1.2 meters in exposed silts and the spring thaw brings a distinct workability challenge. The local Quaternary geology alternates between Halton Till and glaciolacustrine deposits, meaning two adjacent lots can show completely different gradation signatures. Our grain size analysis splits the soil into gravel, sand, silt, and clay fractions, then applies the Hazen formula and the Unified Soil Classification System (USCS) to predict hydraulic conductivity and frost susceptibility. For sites near the escarpment face, where fractured shale weathers into a silty matrix, the hydrometer step becomes critical—standard sieves cannot quantify the sub-75-micron fraction that controls drainage behavior. We regularly pair this test with Atterberg limits to confirm whether those fines are silts or active clays, and with in-situ permeability testing when stormwater infiltration trenches are part of the site plan in St. Catharines.

Grain Size Analysis (Sieve + Hydrometer) for Geotechnical Projects in St. Catharines — Technical reference — St. Catharines

Local geotechnical context

NBCC requires frost protection depth calculations based on the soil's particle size distribution, and St. Catharines is mapped as a zone where frost action can be severe in silty soils. A grain size analysis that skips the hydrometer phase may classify a frost-susceptible silt as a non-susceptible fine sand, leading to undersized footing depths and spring heave damage. The Niagara Peninsula Conservation Authority also evaluates gradation data when reviewing permits near watercourses; a missing hydrometer curve can stall approval for weeks. On the escarpment bench, where thin soil over shale creates perched water tables, the silt fraction directly governs pore pressure buildup during heavy rain events. Our clients in St. Catharines use the full gradation report to satisfy both geotechnical review and environmental compliance in a single submission, avoiding the cost of resampling frozen ground in February.

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Relevant standards

ASTM D422 - Standard Test Method for Particle-Size Analysis of Soils, ASTM D7928 - Standard Test Method for Particle-Size Distribution of Fine-Grained Soils Using the Hydrometer, CSA A23.2-2A - Sieve Analysis of Fine and Coarse Aggregates, NBCC Division B, Section 9.12 - Frost Protection, USCS ASTM D2487 - Classification of Soils for Engineering Purposes

Technical parameters

Parameter	Typical value
Test method (sieve)	ASTM D422 / CSA A23.2-2A
Test method (hydrometer)	ASTM D7928
Sample mass required	500 g for sands, 200 g for silts/clays
Sieve range	75 mm to 75 µm (No. 200)
Hydrometer range	75 µm to 1 µm
Reporting standard	USCS classification + gradation curve
Turnaround time	3–5 business days after sample receipt

Questions and answers

How much does a grain size analysis cost in St. Catharines?

For a combined sieve and hydrometer test on a standard sample, the cost ranges from CA$160 to CA$260 depending on the percentage of fines and whether the sample requires special dispersion treatment. Rush turnaround may carry a surcharge.

What sample size do you need for the hydrometer test?

We require approximately 200 grams of material passing the No. 10 sieve for the hydrometer analysis, plus additional bulk material for the sieve portion. Samples should be sealed in airtight bags immediately after extraction to preserve natural moisture.

Why is the hydrometer test needed if I already have sieve results?

Mechanical sieves cannot accurately measure particles finer than 75 microns. In St. Catharines, many glacial silts fall below this threshold. The hydrometer quantifies the silt and clay fractions that control frost susceptibility, permeability, and compressibility—parameters that directly influence footing depth and drainage design.

How long does a complete grain size test take?

Standard turnaround is 3 to 5 business days. The hydrometer phase requires sedimentation readings at specific time intervals over a 24-hour period. Large projects with multiple samples may need additional time, which we coordinate with your construction schedule.

Location and service area

We serve projects in St. Catharines and surrounding areas. More info.

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