Geosynthetic Clay Liner


GCL Membrane is an impermeability material formed by wrapping natural sodium bentonite material with robust geotextiles. An impermeable gel is formed as a result of the contact of bentonite with water, which is trapped by the self-enclosed geotextiles. In this process, natural bentonite expands about 16-18 times its dry weight and forms an impermeable layer. When water is withdrawn from the environment, it returns to its original state. This cycle is repeated continuously and does not affect the waterproofing properties of the material.

Application and Usage Areas

GeoSeal GCL Membrane is applied by using at least 10 cm thick on the compacted soil or gravel layer, and at least 30 cm under the concrete or reinforced concrete layer, by using it under the soil or gravel layer. It should be applied on flat, gap-free and dry surfaces. It is applied by rolling on the surface on flat areas or by overlapping the joints by at least 30 cm with the help of a construction machine. Roll joints are laid by staggering at least 30 cm. On vertical surfaces, it should be fixed mechanically.

  • Solid waste landfills
  • Mining waste landfills
  • Irrigation, fire and golf course ponds
  • Irrigation channels
  • Water reservoirs
  • Building foundation insulation projects


  • It provides a great cost advantage compared to the application of compressed clay layer.
  • Compared to the clay layer with the same impermeability, it performs the impermeability function better with 100-150 times less volume. It provides significant savings in costs such as storage and transportation.
  • It has superior hydraulic and mechanical properties thanks to natural bentonite and woven and nonwoven geotextiles surrounding it.
  • There is no need for special equipment in laying the rolls.
  • It is much easier and faster to transport and apply compared to the compressed clay layer, which creates much more volume.

Packaging and Storage

The materials are shipped in rolls with a width of 4 – 5 m and a length of 40 – 50 m.

It should be stored in a flat, dry surface and well-drained warehouse, and the products should be covered with a tarpaulin. It should be protected from contact with moisture and water during storage.

Technical Specifications

Top layer (polypropylene nonwoven) (g/m²) 200 – 300
Substrate (polypropylene braided) (g/m²) 100 – 200
Unit weight (g/m²) 4000 – 5000
Swelling index (ml/2g) ≥ 24
Liquid loss ≤ 18
GEOSynthetic Clay COVER
Unit weight (g/m²) 4300 – 5500
Thickness (mm) 5 – 7mm
Roll width (m) / Length (m) 4-5m / 40-50m
Liquid impermeability (m/s) 5×10-11
Tensile strength (kN/m) ≥ 12
Peel strength (N/m) >600