Application
Box welded liners for natural swimming pools
A natural swim pond deserves a liner that looks as good as the water above it. No creases, no folded corners — made to your exact specifications.
Why choose a box welded liner for your natural swimming pool?
No visible folds in the swimming zone
In a natural swimming pool, the liner is on display. Box welding eliminates the bunched corners and creased walls that detract from the appearance of the finished pool.
Large-format capability
Natural swimming pools tend to be large. We can manufacture liners to any size — there is no practical upper limit on the dimensions we can produce.
Regeneration zone integration
Many natural pools include a separate regeneration zone. We can manufacture the liner to accommodate this, including the separation wall and any steps between zones.
What makes a natural swimming pool liner different
A natural swimming pool is a hybrid between a garden pond and a swimming pool — and it places demands on the liner that neither application does alone. The liner must be visually clean, because it is always on display below a metre or so of clear water. It must cope with regular human contact across the swimming zone. And in many designs it must also accommodate a separation wall between the swimming zone and the regeneration zone, where aquatic plants do the biological filtration work.
A flat sheet liner folded into a natural pool produces creased corners and bunched walls that are visible from the pool edge and from the water. A box-welded liner is cut and welded to the exact geometry of the pool — the walls are flat, the base is clean, and the corners are welded seams rather than improvised folds.
Regeneration zones and separation walls
Most natural swimming pools include a separate regeneration zone — a shallower planting area where submerged and emergent aquatic plants filter the water naturally. This zone is typically separated from the swimming zone by a low wall or berm, with water circulating between the two by gravity or a low-head pump. We manufacture the liner to accommodate both zones in a single piece, including the separation wall geometry and any steps or level changes between zones. This eliminates the risk of a join between separate liner panels leaking at the transition.
Material choice for swim ponds
We recommend the 1.0mm heavy-duty grade for natural swimming pools. The additional thickness provides better resistance to UV at the waterline, where the liner is periodically exposed, and to the mechanical stress of regular swimmer contact with the pool base. Both EPDM and Butyl rubber are inert and safe for swimming once installed. For more on material selection, see our choosing the right pond liner material guide.
Shapes we manufacture
What to measure
For a natural swimming pool, provide:
- Overall length and width (m)
- Depth of swimming zone (m)
- Depth of regeneration zone if separate (m)
- Position of any steps or planting shelves
- Desired lip overhang (m)
Frequently asked questions
We recommend 1.0mm heavy-duty pond liner for natural swimming pools. The additional thickness provides greater resistance to UV exposure and the mechanical stress of regular swimmer contact.
Yes. We manufacture liners up to any size. Very large ponds may require a welded-in-situ approach — contact us to discuss the options for your project.
Yes. Our range of pond liners is inert once installed and safe for human contact — the same inert rubber specification used in natural swim ponds and wildlife pools across the UK.
Ready to get a quote?
Send us your dimensions — we'll reply with a price and a technical drawing the same working day.