Composite Geomembrane

Composite geomembrane laminates an impermeable membrane with needle-punched nonwoven geotextile on one or both sides. The membrane provides the barrier; the geotextile protects it from puncture by sharp stones in the subgrade and adds friction against slopes.

One fabric or two? A one-side composite (one geotextile bonded to one membrane) is the standard build for canal and reservoir lining, where the fabric sits against the soil and the smooth membrane faces the water. A two-side composite (fabric on both faces) is specified where the liner is sandwiched between coarse drainage gravel above and rough subgrade below, or where the design calls for friction on both interfaces. If your project has a drainage layer over the liner, a two-side build is usually the safer choice; if the liner is simply laid on prepared soil and covered with water, one side is enough and costs less.

How to size the build-up. Composite geomembranes are described by two numbers: the geotextile unit weight and the membrane thickness. Common pairings are 600 g/m2 fabric with 0.5 mm membrane for canal and pond work, and 800-1000 g/m2 fabric with 1.0-1.5 mm membrane for landfill and mining duty where puncture energy is high. Send us the subgrade description, the cover material and the design head, and we will propose a pairing that satisfies the puncture and friction requirements without over-buying polymer.

Installation notes that save rework. Lay the composite with the fabric side against the subgrade and keep the membrane face clean and dry before welding, because the fabric will wick moisture to the seam. Where two panels meet, the geotextile must be cut back locally to expose the membrane so the wedge can weld polymer to polymer - a seam made through the fabric will not hold. We supply the cut-back detail and a recommended weld window with every order, and geotextile overlaps at the cut-back are re-secured by hand stitching or thermal bonding after the seam passes air testing.

Standards and documentation. The membrane component is produced to GRI-GM13 / GRI-GM17 requirements and the geotextile to common nonwoven specifications, with mill certificates covering membrane thickness, tensile and elongation, fabric unit weight, and peel bond strength between the two layers - the bond strength is the property that determines whether the composite behaves as one sheet or delaminates on site, so we test it per production lot. Third-party inspection before shipment is available through SGS, BV or Intertek.

Combining both functions in one delivered product simplifies procurement and installation - fewer layers to place and fewer interfaces to control.

Tell us the layer structure in your design, the subgrade condition and the required design life - we will quote a matching build-up and confirm lead time within 24 hours.