Field Permeability Testing (Lefranc/Lugeon) in Markham

The Oak Ridges Moraine shapes a lot of what we drill through in Markham. Layers of sand and gravel sit right next to dense glacial till, and the water table can shift fast after a storm. When a contractor hits saturated silt where they expected dry clay, the dewatering plan falls apart. We run the Lefranc test in soil borings to measure hydraulic conductivity directly in the zone that matters. For deeper bedrock, especially where the Georgian Bay Formation shows jointing, we switch to Lugeon testing under pressure. The data we collect on grain-size distribution complements the permeability profile, helping engineers decide if a recharge system makes sense or if they need to redesign the cut-off wall. Markham's rapid development north of Highway 7 keeps our crew busy year-round.

A Lefranc test at the right depth saves more re-design hours than a hundred lab perm tests on disturbed samples.

Process and scope

Markham's transformation from farmland to tech hub meant thousands of foundations went in fast, sometimes without adequate hydrogeological data. Older subdivisions near Unionville sit on low-permeability silty clays, while newer industrial parks around Woodbine Avenue hit sandy lenses that drain freely. Our field permeability testing gives you that distinction. The Lefranc method uses a simple falling or constant head setup inside the borehole at a specific depth, isolating the test section with a packer if needed. The Lugeon test applies pressurized water in rock, measuring take in Lugeon units, typically across five pressure steps. We follow CSA A23.3 guidelines for concrete durability assessment and the Ontario Building Code references for foundation drainage. Every test includes a detailed log with stratigraphy, water level before and after, and the calculated k value in cm/s. We can also pair the results with a plate load test to verify the bearing capacity once the drainage strategy is confirmed.

Local ground factors

The most common mistake we see in Markham is assuming a single infiltration rate from a desktop soil survey. The Rouge River watershed cuts through the city, and a site on the Don River side can behave completely differently from one two kilometers west. If you size a stormwater infiltration gallery based on regional estimates instead of a Lefranc test, you risk underperformance, ponding, or even basement flooding complaints down the line. Over in the bedrock, a contractor once skipped the Lugeon assessment and poured a deep foundation without recognizing open fractures. The grout took four times the estimated volume, the schedule blew out, and the cost followed. We test in situ because the continuum matters: a low-permeability matrix can carry high-conductivity fractures that only a pressurized test will reveal. NBCC Part 4 and local conservation authority guidelines both push for site-specific permeability data when infiltration is part of the stormwater management plan.

Reference parameters

Parameter	Typical value
Test methods	Lefranc (variable/constant head) in soil; Lugeon (pressurized) in rock
Applicable strata	Glacial till, sand lenses, silty clay, fractured shale/siltstone
Borehole diameter	HQ to 8-inch, depending on depth and casing requirements
Pressure range (Lugeon)	Up to 10 bar, with electronic transducer and manual gauge backup
Reporting standard	k (cm/s) for Lefranc; Lugeon units (Lu) with pressure-flow curves
Typical test depth	3 m to 60 m below ground surface in Markham conditions
Relevant codes	CSA A23.3, Ontario Building Code, local conservation authority specs

Related services

Lefranc Testing in Overburden

Falling head or constant head method inside a borehole, with the test section isolated. We target specific soil layers identified during drilling and provide k values for each zone.

Lugeon Testing in Bedrock

Multi-stage pressure testing in rock, typically five steps per test interval. We record pressure and flow in real time, plot the Lugeon curve, and identify fracture flow versus matrix permeability.

Infiltration Feasibility Reports

We combine field permeability data with soil classification and groundwater monitoring to deliver a report that meets Toronto and Region Conservation Authority (TRCA) or municipal requirements for stormwater management.

Frequently asked questions

How much does a field permeability test cost in Markham?

A single Lefranc test during a routine drilling program typically runs between CA$950 and CA$1,350 per test interval. Lugeon testing in bedrock adds mobilization time and pressure equipment, so it falls at the upper end of that range or slightly above depending on depth and number of stages. The total cost depends on how many zones you need to characterize and whether we're already on site for drilling. We'll give you a fixed-price proposal once we review the borehole plan.

When should I use the Lugeon test instead of the Lefranc method?

Lefranc is for soil and very soft rock. Once you're into competent bedrock, especially the fractured shale and siltstone of the Georgian Bay Formation under Markham, the Lugeon test is the right choice. It applies controlled pressure in stages and captures how fractures open or close, which a simple falling head test in soil can't do. If the core shows jointing or you suspect high conductivity at depth, go with Lugeon.

How long does a field permeability test take on site?

A single Lefranc test with setup, saturation, and measurement usually takes 30 to 60 minutes once the borehole is at the target depth. A full Lugeon run with five pressure steps can take 60 to 90 minutes per interval. We plan the sequence with the drilling crew so the tests fit into the normal drilling day without holding up the rig unnecessarily.