Geosynthetic Clay Liner (GCL)

Geosynthetic Clay Liner (GCL)

We manufacturer over sixty different types of GCLs since our plant inception in 1992.  Need a specific GCL for your specific project?  Please call or email us.

Bentofix® Thermal Lock Geosynthetic Clay Liners (GCLs) are needle-punched reinforced composites which combine two durable geotextile outer layers with a uniform core of natural sodium bentonite clay to form a hydraulic barrier. The sodium bentonite clay utilized in Bentofix® Thermal Lock GCL is a naturally occurring clay mineral that swells as water enters between its clay platelets. When hydrated under confinement, the bentonite swells to form a low permeability clay layer with the equivalent hydraulic protection of several feet of compacted clay. Bentofix® GCLs are produced by distributing a uniform layer of the sodium bentonite between two geotextiles. Fibers from the non-woven geotextile are then needle-punched through the layer of bentonite and incorporated into the other geotextile (either a woven or a non-woven). This process results in a strong mechanical bond between the fabrics. A proprietary heat treating process – the Thermal Lock process – is then used to modify and more permanently lock the needle-punched fibres into place. Properties include increased internal shear resistance and long term creep resistance.

We manufacturer over sixty different types of GCLs now since our plant inception in 1992.  Need a specific GCL for your specific project?  Please call or email us.

Superior GCL Performance

Since the late 1980s, GCLs have been specified and used by design engineers, contractors, agencies, and owners as an alternative to soil barriers in various applications. The growing interest in these products stems from the unique properties and advantages they offer. They are very effective as a hydraulic barrier even under high gradient conditions; they are easy to install; more robust against installation stresses and can withstand elongation as well as settlement stresses without significant impact on hydraulic performance. The wide range of GCL uses include landfill caps and base liner applications, dams, canals, ponds, rivers and lakes, and even waterproofing of buildings and similar structures. Numerous laboratory studies have shown the excellent performance capable with natural sodium bentonite GCLs.


By needle-punching fibres through the sodium bentonite clay layer, a completely uniform, reinforced GCL is produced – with shear strength and stability advantages important to any application, such as:

  • Golf course ponds.
  • Stormwater management ponds.
  • Recreational ponds.
  • Landfill cap closures / base liner.
  • Dams/dikes.
  • Vertical trench cutoff Barrier.
  • Groundwater protection cover.
  • Environmental protection barrier under roads and railways.
  • Secondary containment for above ground tanks.


Bentofix® Thermal Lock GCLs represent a cost effective solution, which is both simple and economical. To install, a core bar is inserted through the core, and the roll is suspended from a spreader bar. Ease of installation using a spreader bar allows the contractor to roll out the Bentofix® rolls with a minimal amount of labour. Please contact our technical team for detailed installation recommendations at One truckload of GCL can carry over 6,000 m2 compared to a truckload of native clay which will only cover an area of 40 m2 (based on a 50 cm compacted clay layer). We make over fifty (50+) different types of GCLs at our plant, please contact us to review which one would be more appropriate for your project.


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