Quality Control System

A range of high quality pond liners to suit every project


Quality Control is top priority at Gordon Low

To ensure we consistently produce a top quality product involves a great deal of process management. It begins with selecting the right raw materials, it involves fabrication process control, stock control, packaging and despatch management. Each part of the process has to be closely monitored and this is where choosing a pond liner from GORDON LOW PRODUCTS makes such a difference. We can offer a lifetime guarantee (on flat sheets up to 140 sq.m) because we are supplying a premium product backed up by some of the most respected material manufacturers in this field. Quality does not come cheap, but we constantly monitor material prices to ensure we offer highly competitive products, often against lower grade products.

The life expectancy of a synthetic rubber liner is dependent not only on the level of exposure to the elements but also to any mechanical stress due to incorrect fitting or subsequent ground movement any time after installation. Whereas a relaxed liner below the water line could be expected to last for say 30 to 40 years, under severe mechanical stress (stretch) and exposure to ozone, sun and weathering, this could reduce to 15 to 20 years. Correct installation (including the use of a high quality geotextile underlay) and good pond design will greatly extend the expected life of your liner.


In any manufacturing process, high quality raw material selection is vital to produce a high quality end product. We have sourced (and used for many years) what we believe to be the most effective Butyl Rubbers, EPDM Rubbers and PVC lining materials available.

Like any manufacturing process, raw material selection is vital to produce a quality product. We have sourced (and used for many years) what we believe to be the most effective Butyl Rubbers, EPDM Rubbers and PVC lining materials available.

To understand what makes a good quality rubber liner, you must first know how it is made and how the raw materials themselves are produced. Basically a synthetic rubber compound is a mixture of one or more base rubber polymers, i.e Butyl (IIR - isobutylene isoprene - rubber) or Ethylene-Propylene-Diene-Monomer (EPDM), reinforcing carbon black, fillers, process chemicals, antioxidants and vulcanising agents to give the rubber the required strength, flexibility, exposure resistance and even colour. This compound is blended and then passed through steel rollers which create the thin film of sticky, uncured rubber.

Vulcanising the rubber in an autoclave (baked under pressure) sets or 'cures' the rubber into the tough elastic material we know. The vulcanisation process means that the material differs from all thermoplastic products (i.e. PVC), in that its properties are not affected by varying temperatures. The product is chemically stable and always returns to its original dimensions after stretching. The cross-linked molecular structure gives EPDM and Butyl rubber their unique properties. Ageing or changes in characteristics are negligible despite decades of exposure to the atmosphere, sunlight, UV radiation, chemical fallout, water or major temperature fluctuations.

EPDM and Butyl rubber contain no plasticisers or additives which can evaporate or be washed out over the years which is why they last so much longer than plastic liners. The strength and elasticity of the membrane remain practically unchanged for decades, without shrinkage, brittleness, melting or cracking. The membrane is equally elastic, regardless of whether the temperature is -30°C or +120°C.

The handling process used to carry the uncured rubber has a big effect on the final appearance of the sheet. Prior to vulcanisation the rubber is very sticky and it has to be prevented from sticking to it's self before it is baked. Two common methods used in the manufacture of our chosen rubber lining materials, it is either dusted with mineral talc (as is Firestone EPDM) or supported by a carrier sheet which creates a cloth-like texture impression on the sheet surface (SealEco Butyl and SealEcol EPDM-greenseal)

Different compounds of rubber are used for particular applications and price can vary greatly depending on the type, quality and quantity of polymers used. Obviously all of our liners are manufacturer guaranteed fish and plant friendly, but we can also produce liners in drinking water quality grades when required (WRc approved BS6920).

Cheaper, readily available 'Roofing' grade materials can be highly toxic to fish so beware if choosing cheap alternatives. Always compare material test certificates before offering products for particular applications. With Gordon Low Pond Liners you can rest assured that not only have we selected the best available materials, from recognised manufacturers, but we also have samples tested with independent testing authorities to confirm the quality.


Butyl rubber is the most expensive raw material we use for liners, and is produced in Sweden by SealEco, one of the leading material producers. We fabricate sheets in house from 1.7m wide strips using our own specialised technique. The resulting seam is an incredibly strong 25mm wide overlapping joint produced by heating, under pressure, an uncured jointing tape. This process is extremely reliable and quality ensured by a combination of our own design of welding press and stringent quality control procedures. This process enables us to fabricate Butyl and EPDM sheets in the factory up to 45m x 40m in one piece.

Our manufacturing and quality management process is endorsed by SealEco which makes us an Approved SealEco manufacturing partner.


Batch numbered product identification labels ensure traceability of materials throughout our manufacturing process. Unique batch numbers assigned to each liner manufactured, and our manufacturing control software allows us to trace original raw material used, date of fabrication and even which of our welders fabricated your liner.


Utmost care is taken with packaging our lining products, all heavy items are palletised, covered, strapped and/or shrink-wrapped to ensure maximum product protection during delivery.

Material Approval Specifications :

BS903 - Physical testing of rubber

WRc approval to BS6920:2000

EN13948 - Root penetration test

DIN 4062 - Root penetration test

BS6906/4 - Puncture strength

ASTM G53-84 - UV resistance


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