Hidden Risks of Low-Cost Geomembranes
March 19, 2025
The global geomembrane market is facing major challenges as low-cost alternatives increasingly enter the markets in South America, Africa, Southeast Asia, etc. While these products offer an alternative to well-known and established manufacturers on account of their attractive prices, there are underlaying hidden costs that may come in the form of reduced quality. Unfortunately, more and more manufacturers around the world are joining this trend, in Europe, Middle East and South America.
Over the past decade, some end-users in critical applications, such as mining and waste management, have prioritized short-term savings over long-term value, overlooking the lifetime cost of good quality geomembranes in favor of a more cost-competitive proposal. This approach fails to see the risk of employing low-quality materials which can lead to issues down the line that far exceed the initial cost savings.
Cutting costs at the Expense of Quality
While there are obvious differences between manufacturers in terms of production methods, equipment, local labor and energy expenses, raw materials, etc. these usually amount to limited differences in price, up to 10%, thanks to a well interconnected and highly regulated market where good practices are the common standard.
However, a significant price difference often indicates that proper manufacturing practices are not being followed. Just as you can build a house with straw instead of bricks, you can also build a barrier system using geomembranes that lack critical components. But a house made of straw won’t withstand even the faintest gust of wind, and a lowcost geomembrane won’t maintain its properties for long when exposed to challenging site conditions. This cheap price comes with a trade-off of some of the geomembrane’s most important properties.
Geomembrane formulation: Standard practices
HDPE geomembranes are composed of polyethylene resin, carbon black with a special particle size and various additives, including processing aids, UV stabilizers and long-term antioxidants.
Typically, HDPE geomembranes are manufactured with either smooth surfaces on both sides, a combination of smooth and textured surfaces, or textured surfaces on both sides.
The polyethylene resin used in these geomembranes is produced through the low-pressure polymerization of ethylene, the primary monomer. The resin is usually delivered to the manufacturer in a clear, colorless pellet form. It is then blended with the master batch – containing carbon black and additives – and adjusted to meet he specific formulation requirements. It should be explicitly noted that regrind or rework pellets – those that have been processed by the same manufacturer but never used in the field – are often incorporated into the extruder during manufacturing in low percentages (less than 3%).
This is distinct from reclaimed, recycled, or post-consumer materials, which should never be included in the formulation in any quantity.
Carbon black is used in geomembrane formulations primarily for stabilization, especially to enhance ultraviolet light resistance. It is typically added as a preformulated concentrate in pellet form, known as ‘master batch’, which includes carbon black and possibly antioxidants within a carrier resin. The carrier resin should match the host resin in terms of density and melt flow characteristics.
Additives are integrated into HDPE geomembrane formulations to prevent oxidation, enhance longterm durability, and aid in the manufacturing process. They function as a protective barrier for the geomembrane, shielding the polyethylene’s molecular structures from oxidative and/or UV degradation. Over time, however, these aditives deplete due to prolonged exposure to environmental elements. Once this protection disappears, the geomembrane becomes susceptible to damage and begins to lose its original properties. The quality of the additives is critical, as it directly impacts how long the geomembrane maintains its intended performance characteristics.
Specifying HDPE geomembranes based on additives or groups of additives is challenging because these formulations are often proprietary. Additionally, ongoing research and development continually lead to changes in additive compositions.
Sub-standard practices
To understand the risks of using low-cost geomembranes, it’s important to look at some of the practices conducted by low-cost manufacturers as opposed to the recommended standards and practices for geomembrane formulation explained in the previous section.
Recycled Resins
Recycled resins are not allowed under standard specifications like GR GM-13 but are sometimes used to cut costs. Their inclusion can result in unpredictable material behavior under stress, such as in-plane separation (when the different geomembrane layers don’t “stick” to each other) and can introduce unwanted contaminants. In applications involving potable water, these contaminants can pose a serious health risk for the end-consumer in the long term.
As mentioned earlier, one common misconception is to equate the use of regrind resins with recycled ones. Even though regrind resins are reprocessed from already manufactur

caused by die build-up.
ed materials, these are used only at low concentrations (less than 3%) and maintain all their antioxidants. Recycled resins, on the other hand, usually have depleted their antioxidants already before reprocessing, resulting in reduced durability from the get-go.
Using recycled resins can also cause problems in the production cycle in geomembranes produced by the blown method. Because the recycled resins have seen their molecular structure compromised, they cause problems when melting with the rest of the virgin resin, resulting in areas of poorly melted and cross-linked polymer that has spread along the surface as the bubble exits the
ring extruder, creating small holes or tears, which are called “unmelts”, “gels”, or “die build-up”.
Use of Barefoot Resins and low-cost additives
“Barefoot resin” is an industry term for polymer resins that lack additives in their formulation. Unlike fully formulated resins such as Marlex 306/307, barefoot resins contain only the most basic chemical components required to qualify as a resin. These resins are later mixed with inexpensive, locally sourced additives, often leading to geomembranes with reduced durability properties and poor stress crack resistance.
This results in misleading technical data sheets, where the property values seem to be equivalent to those from established manufacturers. However, the duration for which these properties remain stable is significantly reduced by the use of cheap additives. This poses a serious issue in environmental applications, mining waste management, or ponds for irrigation, where geomembranes are expected to perform effectively for years or even decades.The antioxidants and stabilizers used may initially show promising ‘Standard Oxidative Induction Time’ and ‘High-Pressure Oxidative Induction Time’ results. However, these less effective and short-lived additives tend to degrade quickly when exposed to higher temperatures and UV light, significantly reducing the geomembrane’s lifespan and performance.
Mixing different types of polymers
Another questionable practice is blending LLDPE (Linear Low-Density Polyethylene) or PB (Polybutylene) with non-compatible grade resins to artificially improve stress crack resistance. While this practice may provide temporary enhancement in laboratory tests, it can lead to significant failures under actual site conditions. Improper grade resins may lack the necessary long-term durability and performance characteristics required for demanding applications. Consequently, geomembranes incorporating such blends may exhibit compromised resistance to environmental stress and chemical exposures, not to mention a reduction in the quality of the welding.
Tampering with Thickness and Length
To avoid detection during quality inspections, some geomembrane manufacturers may reduce the thickness of the geomembrane in the middle of the rolls or shorten the length of each roll. These deceptive practices can lead to serious problems in projects that require precise specifications and consistent material properties. Reduced thickness in the middle of the rolls can in turn compromise the geomembrane’s overall strength, while shortened roll lengths can result in insufficient coverage and increased waste during installation. Such discrepancies not only affect the geomembrane but can also lead to costly project delays and compliance issues, undermining the integrity of the entire installation.
What Can Be Done?
When a price is unusually low compared to the industry average, it often signals compromises in the material’s quality and performance. Buyers must take proactive steps to ensure transparency in the supply chain, confirm adherence to international standards, and rigorously inspect and test geomembranes for compliance before making a purchase.
Prioritizing certified, high-quality materials is essential for safeguarding project success and supporting the long-term credibility of the geomembrane industry.
To uphold these standards, installers and specifiers should conduct independent CQA on delivered materials. This should include third-party audits and laboratory testing from certified and renowned institutions to verifythat the geomembranes meet all project specifications