Pool Liner: Selection, Installation, Avoiding Wrinkles, Repair
The pool liner is the watertight inner skin of your pool and at the same time determines its appearance. Whether it stays permanently tight and lies wrinkle-free is decided by your choice of material, substrate preparation and installation temperature – not only when you fill it with water.
Liner Thicknesses and Versions
Pool linings fall broadly into two families. Prefabricated inner liners for steel-wall, polystyrene and prefabricated pools are supplied precisely fitted as a round, oval or figure-eight liner and are hung in place without welding. Swimming pool or pool liner membrane sold by the metre, by contrast, is cut to size on site and welded – typical for masonry or concrete pools and for refurbishment.
| Version | Thickness (typical) | Application |
|---|---|---|
| Standard inner liner | 0,4 mm | round pools, low stress |
| Reinforced inner liner | 0,6-0,8 mm | larger pools, greater robustness |
| Reinforced pool liner | approx. 1,5 mm | concrete/masonry pools, weldable, refurbishment |
The fabric-reinforced (armoured) 1,5-mm liner is considerably more tear-resistant and can be permanently welded with hot air, but it calls for expertise. For the finish you also choose between a smooth surface and a slip-resistant liner for steps and floor, as well as between various colours and patterns with a UV- and chlorine-resistant top layer.
Fastening and Connection
You should clarify how the liner is held at the top of the pool edge before you buy, because the bead must match the profile:
- Overlap bead: The liner is pulled over the handrail and hangs freely – the simplest solution for steel-wall pools.
- Hook-in bead: A plastic bead clicks into an edge profile, so the liner sits more tightly and neatly.
- Wedge/keder bead: A keder is drawn into a clamping or keder rail mounted on the wall – common with reinforced liners and refurbishments.
At the skimmer, inlet nozzles and lights, the liner is clamped over flange gaskets and only cut open afterwards. This creates a watertight transition between the soft liner and the ABS or V4A fittings.
Preparing the Substrate and Geotextile
Every unevenness will later show through in the liner, and every burr can puncture it. The substrate must therefore be clean, load-bearing and smooth: vacuum the floor and walls, countersink protruding screw heads, remove burrs, take sharp stones out of the floor build-up and form the floor-to-wall edge as a soft cove.
A pool geotextile (protective fleece, around 300-400 g/m² depending on the stress) belongs on the prepared substrate. It protects the liner from being pushed through and from mechanical damage, evens out small irregularities and buffers condensation and residual moisture. The sheets are laid overlapping, carried up the wall and fixed in place. For a refurbishment, first remove the old liner completely and check the exposed substrate for cracks and pockets of moisture.
Installing the Liner Wrinkle-Free – Temperature Is Key
Plasticised PVC is temperature-dependent: in the warmth the liner becomes elastic and can be pulled smooth, whereas in the cold it turns stiff and tends to form permanent wrinkles. So install it on a sunny, ideally windless day and let the liner acclimatise beforehand, spread out in the sun, so that it is warm and supple.
- Hang the liner in centred and align it to the seam or pattern lines so that it is evenly distributed all around.
- Smooth the liner from the centre outwards and consistently push wrinkles out towards the edge.
- Smooth out floor wrinkles with soft shoes or clean socks – never with a hard tool.
- Fill with water slowly. Even the first few centimetres press the liner into place; as long as there is only a little water in the pool, wrinkles can still be smoothed out. Once the water pressure is there, they are almost impossible to remove.
Only cut out the fittings once the water has drawn the liner neatly into place and there is no longer any tension in the corners and edges.
Typical Fault Patterns and Their Causes
Most complaints can be traced back to just a few causes. This overview helps you correctly classify a type of damage:
| Fault pattern | Probable cause |
|---|---|
| Wrinkles on the floor | liner installed too cold, or water filled too early/too fast |
| Tension wrinkles in the corners | liner not hung in centred, or the size does not match the pool |
| Blisters behind the liner | water or condensation behind the liner, missing drainage, leaking penetration |
| Tears at edges/burrs | sharp or rough substrate, missing or too-thin geotextile |
| Hardening, fading, wrinkles at the water line | permanently incorrect water values (pH/chlorine) and UV exposure |
Since many of these patterns can only be told apart clearly in a photo, it is worth documenting the damage before repairing it.
Repair – Above and Below Water
Small holes and cuts can be repaired underwater without draining. Use an underwater repair kit with a suitable plasticised-PVC or liner adhesive – not the hard PVC pipe cement from the pipework, which does not bond soft liner permanently. Cut the patch round (corners lift off first), apply the adhesive, guide the folded patch underwater to the spot and press it on wrinkle-free.
Above water, a more durable bond is possible: lower the water enough to expose the spot, dry and degrease it thoroughly, stick on the patch and let it cure. Drain a liner pool only as far as necessary and never completely: a liner that falls dry can shrink and harden, so that it can no longer be laid wrinkle-free afterwards; with a high water table there is also the risk that the liner or the entire pool floats up. For large tears or opened seams in a reinforced 1,5-mm liner, hot-air welding by a specialist company is the right solution. If blisters or washouts appear, first fix the cause – that is, the water behind the liner and any missing drainage – otherwise the damage will return.
Hanging in a Pool Liner and Installing It Wrinkle-Free
- Check and clean the substrate Vacuum the floor and walls, remove burrs and protruding screw heads, sort out sharp stones and form the floor-to-wall edge as a soft cove.
- Lay the geotextile Lay the pool geotextile overlapping on the floor and walls, carry it up the wall and fix it in place so that the liner rests protected all around.
- Acclimatise the liner On a warm, sunny day, let the liner warm up spread out in the sun until the material is supple and elastic.
- Hang the liner in centred Hang the liner in centred and align it to the seam or pattern lines so that it is evenly distributed all around and no tension arises.
- Smooth out wrinkles Smooth the liner from the centre outwards, push wall wrinkles to the edge and smooth out floor wrinkles with soft shoes or socks.
- Fill with water slowly Let the water run in slowly and use the first few centimetres to smooth out any remaining wrinkles before the water pressure fixes them in place.
- Cut out and seal the fittings Only once the liner lies neatly, clamp the skimmer, nozzles and lights over the flange gaskets and cut out the liner from the inside.
Bill of materials
Example – please verify with a specialist. Parts and quantities depend on the installation; sizes shown are examples.
| Component | Size | Art. No. | KLN No. | Qty |
|---|---|---|---|---|
| Pool inner liner / lining membrane | – | – | – | Matched to pool shape and fixing method (overhang, hook-in or keder bead); choose thickness according to loading |
| Pool fleece (protective fleece) | – | – | – | Underlay fleece against puncturing and residual moisture, laid with overlaps |
| Underwater repair kit | – | – | – | With soft-PVC / liner adhesive and patch material – not to be confused with rigid PVC pipe cement |
FAQ
Which liner thickness should I choose for my pool?
For steel-wall and prefabricated pools, an inner liner of 0,4 to 0,8 mm is usually sufficient; for masonry or concrete pools and refurbishments, the reinforced, weldable 1,5-mm liner is considerably more robust.
In what weather is it best to install a pool liner?
On a warm, sunny and windless day. Plasticised PVC is elastic in the warmth and can be pulled smooth, whereas in the cold it becomes stiff and wrinkles easily.
How do I get wrinkles out again?
As long as there are only a few centimetres of water in the pool, wrinkles can be smoothed out from the centre outwards. Once the full water pressure is present, floor wrinkles are almost impossible to remove.
Can I repair a hole underwater?
Yes, small holes can be patched with an underwater repair kit and plasticised-PVC adhesive. Cut the patch round and press it on wrinkle-free.
Do I absolutely need a geotextile under the liner?
It is strongly recommended. The protective geotextile prevents sharp spots from puncturing the liner, evens out small irregularities and buffers residual moisture from the substrate.
This guide provides general technical orientation and does not replace professional planning. Safety-, electrical- and permit-relevant work must be carried out by qualified specialists.
