Geomembrane liner FAQ

A geomembrane liner is a synthetic sheet with very low permeability that is used as a barrier to stop liquid or gas moving through soil. In the UAE the sheet is normally high-density polyethylene (HDPE), rolled out over a prepared subgrade and heat-welded panel to panel so the finished lining behaves as one continuous membrane. Permeability of HDPE sheet is in the order of 10^-13 cm/s, which is why it is specified for reservoirs, lagoons and landfill cells rather than clay or concrete alone.

HDPE sheet itself is effectively impermeable — water does not pass through the polymer in any meaningful volume. What decides whether the finished basin holds water is the seams and the details. Panels joined with a correctly set dual-track wedge weld, tested by air pressure, and terminated in a proper anchor trench will hold; the same sheet installed with cold laps, unsealed pipe penetrations or an untested extrusion weld will not. This is why installation and welding matters more than the sheet grade on most projects.

As a working rule for UAE projects: 0.5–0.75 mm for aquaculture and decorative ponds, 1.0 mm for farm and irrigation reservoirs, 1.5 mm for wastewater lagoons, TSE storage and landfill base liners, and 2.0 mm where there is chemical loading or plant traffic on the lining. Head of liquid, exposure to sun and the roughness of the subgrade all push the specification upward. The full breakdown is on the thickness and roll size page.

“Pond liner” describes the job; “geomembrane” describes the material. Most pond liners sold in the UAE are geomembranes — usually HDPE or LLDPE sheet. The difference you will notice in practice is grade: a light PVC or LDPE pond liner sold by the metre suits a garden feature, while a welded HDPE geomembrane is what a contractor uses for an irrigation reservoir or a fish farm that has to last decades in direct sun.

Buried HDPE geomembrane has a design life measured in decades. Exposed sheet in Gulf conditions is the harder case: carbon black loading and antioxidant packages are what carry the membrane through continuous UV and surface temperatures that regularly exceed 70 °C on a black liner in summer. A 1.5 mm exposed liner specified to GRI-GM13 and installed with proper slack for thermal movement is generally expected to serve well beyond 20 years; covering the liner with soil or water extends it considerably.

Yes. Sheet is delivered and crews mobilise to Dubai, Abu Dhabi, Sharjah, Ajman, Ras Al Khaimah, Fujairah, Umm Al Quwain and Al Ain. Send the basin dimensions through the enquiry form and you will get a quantity take-off and price back.

Containment, in every form: irrigation and firewater reservoirs, farm and aquaculture ponds, canal and channel lining, sewage and TSE lagoons, landfill base liners and caps, mine and quarry water management, chemical bunds and secondary containment, tunnel and basement waterproofing, and floating covers over stored water to cut evaporation.

HDPE is the polymer; a geomembrane is the product made from it. High-density polyethylene is the most widely used geomembrane material worldwide because it combines chemical resistance, UV stability and low cost. Geomembranes are also made from LLDPE, PVC, EPDM and bituminous compounds, but in the UAE the default is HDPE.

Yes, and repairs are routine. A puncture is patched with a round-cornered piece of the same sheet extrusion-welded over the damage, then vacuum-box or spark tested. The difficulty is rarely the repair — it is finding the hole under water or under soil cover, which is what an electrical leak location survey is for.

Not always, but often. On graded sand with the stones picked out, a geomembrane can sit directly on the subgrade. On gatch, crushed rock, reclaimed ground or anywhere the head of liquid is high, a nonwoven cushion geotextile between subgrade and membrane is what stops long-term puncture. It costs a fraction of the sheet and saves the lining.

By heat, not adhesive. Long production seams are made with a dual-track hot-wedge welder that fuses two overlapping panels and leaves an air channel between the tracks so the seam can be pressure tested end to end. Patches, penetrations, tie-ins and repairs are extrusion-welded with molten HDPE rod. Solvent and tape joints have no place in an engineered lining.

It expands. A black liner in direct sun can reach 70 °C or more and grows measurably; at night it contracts and pulls tight. Panels are therefore deployed with deliberate slack, welding settings are adjusted through the day as ambient temperature climbs, and welding is often programmed for early morning or night. A liner welded drum-tight at dawn will be under tension by mid-afternoon.

A trench cut around the crest of the basin, usually around 500 × 500 mm, into which the edge of the liner is run and then backfilled. It holds the membrane against wind uplift and against the pull of the sheet on the side slopes. Terminating a liner without one is the most common reason a lining peels off a slope in the first windy season.

HDPE sheet intended for potable storage should be certified for contact with drinking water. Tell us at enquiry stage if the basin is for potable supply so that the correct grade is quoted and the certification supplied with it.