Materials

HDPE (High-Density Polyethylene) is the most commonly used membrane type worldwide. Great longevity covered or exposed. Excellent resistance to many chemicals, even solvents. Good value for money. Mostly black in colour, but can be made other colours (quantities apply). Useful range of thicknesses. Wide panel width (eg. 7 m or more). Not suitable for prefabricating into large sheets offsite. May crack if creased or folded. Most brands certified suitable for potable water contact/containment. Available in smooth or textured finish.

Textured one or both sides. Useful in improving the friction at the interface between the liner and the subgrade …taking some of the “load” away from the anchor trench. Also reduces slipperiness when personnel walk on the liner (while installing and when in use). Slightly more expensive than smooth. Often specified for lining Landfill cells, and on pond batters.

LDPE (Low Density Polyethylene) & LLDPE (Linear Low Density Polyethylene) has many of the characteristics of HDPE, but more flexible (and may be folded). Not quite as chemical- or UV-resistant as HDPE. Usually Potable grade. Often preferred for floating covers.

GCL (Geosynthetic Clay Liner) is comprised of a layer of Sodium Bentonite/ Montmorillonite captured between 2 geotextile layers. It can be used as a Primary liner (confined under an earth backfill layer), but more often used as a secondary liner under a HDPE or other Primary liner.More or less a handy alternative to a Compacted Clay Liner (CCL)

Geotextile is available either Woven or Non-Woven. It is a type of filter cloth that comes in various grades & thicknesses. Often used as a protective layer under a geomembrane liner, or as a cushion layer over a geomembrane liner to protect that liner from “bruising” when backfilling (eg in a Landfill). Used as a filter either side of a Geonet/Drainage Net.  Many other uses in civil construction.

Polypropylene (PP) is available as un-reinforced or with a reinforcing scrim….which may be useful in a floating cover. PP has had a chequered history in the lining sector. More flexible than HDPE, so can be quite user-friendly. Probably not as “thermo-responsive” as HDPE (so less rippling in sunlight). Probably not as durable as HDPE. Thinner gauges very suitable for prefabricated liners….eg up to say 2,500 m² or larger.

Enviroliner is not quite as flexible as PP; this thinner version of PE geomembrane can be prefabricated into quite large sheets, for quick (often DIY) site installation. The Canadian manufacturer backs his product with an extended Warranty.

Canvacon (the Genuine Australian made coated/woven Poly) has been used in Australia for lining ponds and dams for over 30 years. It can be prefabricated into quite large sheets… (Eg 5,000m²) and transported to your nominated address. This allows for DIY Installation in some cases. Genuine Canvacon will last up to 6 or more years exposed in the Australian Sun, but much longer if buried.

PE or PP formed into a “net” or “lattice” that allows fluids to flow through. Often used as a “spacer” between the Primary and Secondary geomembrane liner, so that if the Primary Liner should leak, the fluid will drain (eg. into the leak-collection sump) quickly, without heat build-up.

E-Vap Cap was developed for use in Evaporation Control Covers. It is designed to float on top of the dam, protecting the water from evaporation. In the event of rain, there are drainage holes throughout the material, allowing water to seep into the storage facility. For more information go to www.evaporationcontrol.com.au

Two or more of the above items bonded together. Eg. A Drainage Net encapsulated in a Non-Woven Geotextile; the geotextile filters out finer particles (silt/clay) that would otherwise tend to clog the drainage net. May be used under a liner system, in contact with the soil /CCL subgrade, to handle Groundwater.