We still see contractors in Laval who skip the full hydrometer test and just run a quick sieve. Then the fill gets placed, the fines migrate, and six months later the parking lot is a mess of differential settlement. The till-derived soils across Laval, especially in the eastern sectors toward the Rivière des Prairies, carry a surprising amount of silt and clay that a simple sieve analysis will miss. A complete grain size distribution curve — combining mechanical shaking and sedimentation — gives you the numbers that actually matter for compaction specs, frost protection, and drainage design. In a city where winter penetrates deep into the subgrade, guessing the fines content is the fastest way to lose your paving warranty. The team here runs both portions under one protocol, so you get a single report with the full particle-size range, ready for the City of Laval’s engineering department or your geotechnical consultant.
A sieve-only curve in Laval’s silty tills is a half-finished job — the fines dictate frost heave, drainage, and long-term compaction stability.
Local considerations
We see it often in Laval’s industrial parks: a contractor imports granular fill from a Drummondville pit, assumes it is clean sand, and skips the hydrometer. Then a spring thaw hits and the parking lot heaves unevenly because the ‘clean’ fill actually carried 12% fines. That is a six-figure repair that a grain size analysis would have prevented. The risk isn’t just frost — it is also about permeability. Soils with more than 5% passing the 75 µm sieve can hold water against foundation walls, leading to hydrostatic pressure problems that no weeping tile can fix if the backfill itself is the culprit. In the residential sectors of Chomedey and Sainte-Dorothée, where basement walkouts are common, misclassifying a silty sand as free-draining creates chronic dampness. The full sieve-plus-hydrometer report gives you the coefficient of uniformity and gradation curve needed to make an informed call on filter compatibility, frost susceptibility, and compaction specification.
Frequently asked questions
How much does a grain size analysis (sieve + hydrometer) cost in Laval?
A combined sieve and hydrometer test on a single sample typically runs between CA$120 and CA$280, depending on whether you need the full curve or just one portion. Expedited turnaround adds a surcharge. We quote by the sample, so if you are running a quality control program with multiple lifts, we can set up volume pricing. Contact the lab with your project specs for a firm number.
How long does the hydrometer portion take?
The hydrometer sedimentation test requires a minimum of 24 hours of undisturbed settling time, plus sample preparation and dispersion. Most combined reports are ready in 48 to 72 hours from sample receipt. If you only need the sieve portion, we can often turn that around the same day.
What sample size do you need for the full test?
For a combined sieve and hydrometer analysis, we typically need about 500 grams of material passing the No. 10 sieve for the hydrometer portion, plus enough bulk sample to represent the coarse fraction — usually 2 to 5 kg total. If the soil contains gravel larger than 19 mm, we will need more material to get a statistically valid split. We supply sample jars and instructions.
Do you provide the gradation curve ready for City of Laval permit submissions?
Yes. The final report includes the semi-log particle-size distribution plot, the coefficients of uniformity and curvature, and the percent gravel, sand, silt, and clay fractions — formatted to meet the City of Laval’s engineering submission requirements. We also include chain-of-custody documentation and lab accreditation references.
