" />Even with careful installation, an HDPE geomembrane liner may develop small damages from sharp objects, equipment or settlement. Timely repair with patch welding keeps the liner watertight and extends its service life. This article explains the repair steps and prevention measures.
Inspect the Liner Surface
Walk over the liner and check the surface for scratches, punctures, holes or open seams. Mark each damaged area clearly before starting the repair. A full inspection after installation and before backfilling helps find problems at an early stage.
Prepare the Patch
Cut a patch from the same membrane material, large enough to overlap the damaged area by at least 100 mm on each side. Round the patch corners to reduce stress concentration. Clean the repair area with a dry cloth to remove dust and moisture.
Weld the Patch
Use a hot air welder or extrusion welder to fuse the patch onto the liner. For small holes, an HDPE welding rod can fill the opening, followed by a surface patch. Weld from the center outward to avoid trapped air, and check the weld edge for complete fusion.
Test the Repaired Area
After welding, test the repaired area by air pressure or by a spark test if required by the specification. For water-retaining structures, observe the repaired area after filling. Any weak weld should be re-welded before the liner is accepted.
Prevention Measures
Place a geotextile cushion under the liner, keep equipment off the membrane surface, and protect the liner with soil cover soon after installation. These measures reduce the risk of damage and the need for frequent repairs.
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