The question arises in almost every pool renovation project: is it better to install a liner or a reinforced PVC membrane? Both products serve the same function — ensuring the watertightness of the pool and its aesthetic finish — but they belong to two distinct technical families, with concrete differences in terms of lifespan, support compatibility, budget, and implementation. The choice is not neutral, and it is not just a matter of thickness.
As a French manufacturer of PVC coatings for pools for several decades, CGT Alkor produces both families of products in its factory in Liancourt. This position provides a unique perspective: we see both coatings aging on thousands of pools, in very varied climates and uses. The following guide synthesizes these observations, without artificially opposing the two solutions — each has its legitimate area of use — but helping to identify which is best suited for a given project.
Two families of coatings often confused
Let’s start by clarifying the vocabulary. In common language, people often refer to a “liner” to designate any PVC pool coating. Technically, however, the two products have nothing to do with each other in their structure.
The liner: a single sheet of PVC
The liner is a single sheet of flexible PVC, manufactured in the factory to the precise dimensions of the pool, then delivered and installed as a single piece. Depending on the range, the PVC can be glossy, printed, or textured; common thicknesses are around 75/100 for entry-level references and 85/100 or more for higher qualities. CGT Alkor offers six collections of liners for 2026, including the 3D Liner anti-slip in 95/100, the RT4000 printed range with designs like Skyline or Butterfly Pearl, and the classic RT3000 and Standard in solid colors.
One point to note: CGT Alkor liners are marketed exclusively in B2B, aimed at specialized liner manufacturers, never sold directly to individuals. The end customer therefore purchases their liner through a pool professional or a liner shop.
The reinforced membrane: three layers and a polyester mesh
The reinforced membrane — often simply called “membrane” or “reinforced PVC” — is a product structured in three layers: an upper PVC sheet that carries the pattern and provides protection, a polyester reinforcement grid in the center, and a lower PVC sheet in contact with the support. Standard thicknesses are 150/100 (1.5 mm) for smooth ranges like Aquacolor and Aquadecor, and 180/100 (1.8 mm) for textured anti-slip 3D ranges like Aquasense Signature, Aquasense, and Aquastone.
Unlike the liner, the reinforced membrane is not delivered pre-formed. It arrives in rolls that the installer cuts and welds on-site, to the exact shape of the pool. This difference in implementation is the source of most of the distinctions that follow.
Waterproofing: what the polyester mesh changes
The waterproofing of both products relies on the impermeable nature of PVC. The difference lies in their behavior over time and under stress. The liner, being a single sheet, absorbs thermal variations and micro-movements of the pool through tension and deformation; it can “work,” which is an expected behavior. The reinforced membrane, thanks to the polyester mesh sandwiched in, maintains a much higher dimensional stability and is better resistant to puncture tears — a poorly trimmed edge of a sealing piece, an object that falls, a poorly adjusted brush stroke.
Resistance to mechanical and thermal stresses
In a pool subjected to significant temperature fluctuations, prolonged heated water, or intensive use (family pool used daily, second home with treatments in the owner's absence), the reinforced membrane manages cycles better. Manufacturers and installers often observe a more predictable behavior of reinforced PVC in such usage scenarios.
Free-form pools and atypical basins
As soon as a pool deviates from the standard rectangle — free form, bean shape, overflow, Roman steps, submerged beach, mirror pool — the pre-formed liner becomes an industrial headache or hits its limits: sensitive corner welds, difficult manufacturing tolerances on complex shapes. The reinforced membrane, welded on-demand on-site, adapts to any geometry. This is why almost all overflow pools, public basins, and very free forms are equipped with reinforced membranes rather than liners.
Lifespan: comparing the right indicators
The announced lifespans for both families partially overlap but the actual conditions differ. A properly maintained liner often lasts 10 to 15 years on a classic residential family pool, with a gradual loss of color and elasticity. A reinforced membrane lasts longer under the same conditions, and CGT Alkor commercial ranges like Infinity 30 and Infinity 60 are guaranteed for 20 years in collective use.
These figures should be read with caution. Lifespan strongly depends on water quality (repeated chemical imbalances, excessively high chlorine), UV exposure, temperature cycles, and — a major factor — the quality of installation. A careful installation on a properly prepared support will extend the life of a coating beyond the average, while a sloppy installation will lead to renovation well before the end of its lifespan, regardless of the product.
Compatibility with the support: concrete, shell, tiling, wood
The choice between liner and reinforced membrane is often determined by the nature of the existing support. This is the most decisive criterion in renovation.
New or renovated concrete basin
Both solutions are suitable. In new builds, the liner offers a more contained cost and a proven aesthetic; the reinforced membrane provides greater longevity and adaptability for shapes that deviate from the ordinary. In the renovation of a concrete basin that shows superficial cracks or a degraded support, the reinforced membrane is often the best choice: its polyester mesh better absorbs the defects of the support and small masonry repairs than the liner, which requires a smoother and more regular support.
Polyester shell and acrylic basin
Shells are not designed to receive a PVC coating as standard. In rare cases — a very degraded shell that one wants to save — a reinforced membrane may be considered by an experienced installer, provided that specific support preparation is done. The liner, on the other hand, is poorly compatible with this type of basin. The pragmatic rule: if the basin is a still healthy shell, it is repaired or gelcoated; if the shell is unusable, it switches to a reinforced membrane with a technical opinion.
Tiled pools in renovation
Loose tiles, failing joints, leaking waterproofing: the reinforced membrane solves most of these problems without demolition. It is installed directly over the existing tiles, after preparation (leveling of hollows, treatment of points). The liner, conversely, generally requires the removal of the tiles to find an acceptable support, which turns the project into a heavy renovation. In this specific case, the reinforced membrane has a clear economic and technical advantage.
Wooden pools and metal structures
Above-ground or semi-buried wooden pools traditionally use a liner, suited to their structure and standardized dimensions. The reinforced membrane is rarely used here: the investment is generally not justified for this type of basin. For a wooden pool, the liner remains the reference solution.
Installation: two implementation logics
The installation is the element that most clearly separates the two products on-site.
Liner installation: tension and precision of dimensions
A liner is manufactured to the exact dimensions of the pool based on the provided measurements. On the installation day, the installer unrolls, positions, tensions under suction, and allows the water to rise gradually while readjusting the folds. The final quality depends heavily on the precision of the initial dimensions and the regularity of the support. A trained pool professional can install a liner in one to two days on a classic residential pool.
Reinforced membrane installation: hot air welding on-site
The reinforced membrane requires specific skills: hot air welding with a Leister-type device, controlled heating temperature, execution of angles and sealing pieces, and checking the waterproofness of the welds. The choice between overlapping installation or edge-to-edge installation depends on the range and the preferences of the installer, with each technique having its proponents. The project takes longer than a liner installation — generally three to five days on a standard residential pool — and the labor cost follows.
Technical mastery is not interchangeable. An excellent liner installer is not automatically a good reinforced membrane installer, and vice versa. Training programs like CGT Alkor Academy, offered over three days with two levels of certification, exist specifically to structure the skill development of professionals on the membrane.
Aesthetics and design choices
Both families now cover a very wide aesthetic range. On the liner side, CGT Alkor's printed ranges like RT4000 AQ (Granite, Fiji, Basalt, Gold) or the Pearl collection (Cyrus Blue, Santorini, Butterfly) visually compete with membrane finishes. On the reinforced membrane side, the 2026 offer covers six residential collections from smooth solid colors (Aquacolor) to high-end textured 3D with 20% recycled PVC (Aquasense Signature).
The anti-slip 3D textures are, in practice, the monopoly of the reinforced membrane: no liner currently offers the same level of anti-slip relief as the Aquasense, Aquastone, or 3D Liner ranges in their textured versions. For submerged beaches and stairs, this is a strong argument.
Budget: why the ranges don’t tell the whole story
It would be dishonest to give a price per square meter for either solution. The total cost of a coating depends on so many variables — dimensions, shape, condition of the support, accessibility of the site, provision or not of accessories, region, seasonality, choice of range — that any generic range proves false as soon as it is confronted with a real project.
What can be said without risk: for equivalent surface and quality, the reinforced membrane costs more than the liner, mainly due to installation labor and material costs. The additional cost is justified in cases where longevity, compatibility with a difficult support, or the anti-slip 3D aesthetic provide a tangible benefit. On a rectangular family pool in good condition, the liner may remain the most rational solution. On a complex renovation or a free-form pool, the reinforced membrane regains the economic advantage over time, even with a higher entry ticket.
The quote remains the only serious tool for estimating a project. A professional who refuses to visit the site or who quotes a price over the phone without having seen the pool is not reliable, regardless of the solution.
Maintenance, winterization, indoor pool usage
Regular maintenance is similar for both families: water balance, regular brushing, monitoring chlorine and pH parameters, cleaning the waterline. The reinforced membrane tolerates occasional deviations a bit better, but repeated shock chlorine or chronically deviated pH damages all PVC coatings, without exception.
For covered indoor pools, the reinforced membrane is often preferred: constant heat, high humidity, sometimes more aggressive treatments, prolonged use throughout the year. Liners may be suitable for domestic indoor pools, but commercial installations — hotels, thalassotherapy centers, collective pools — are almost exclusively in membranes, specifically in ranges certified for public use like Aquaceram anti-slip 1.8 mm or Infinity 40% recycled PVC guaranteed for 20 years.
Replacing a liner with a reinforced membrane: is it possible?
Yes, and it is one of the most common renovations in the French residential pool market. An end-of-life liner is removed, the support (often concrete or steel panel) is checked and prepared, and then the reinforced membrane is installed by welding. The operation is carried out without major technical difficulties, provided that the support remains sound or that defects are repaired beforehand.
The opposite — replacing a reinforced membrane with a liner — is technically possible but rarer, mainly because owners who have already invested in a membrane rarely want to go back. In many cases, the renovation consists of installing a new reinforced membrane over the old one, after diagnosing the support and the existing membrane.
Finding a trained installer for CGT Alkor reinforced membrane
Once the technical choice is made, the next step is to identify the right professional. For the reinforced membrane in particular, the installer’s competence weighs as much, if not more, than the choice of range. The platform for connecting pool professionals, installers, and individuals community.cgt-alkor.com was designed for this step: free account, geographical filters by department, visibility of certified profiles and CGT Alkor ambassadors, project submission directly consultable by installers in the area. The tool does not replace on-site dialogue; it simply allows for quickly identifying competent professionals in the desired intervention area.
For the product part, all 2026 ranges — residential, commercial, liner and membrane collections, accessories, and marketing tools — can be consulted at cgt-alkor.com. It is always wise to ask your installer to present physical samples before making a decision: colors and textures appear differently on screen and in a full water basin.