WHY WATER GARDENERS CHOOSE OUR BOX WELDED BUTYL LINER
Precision-Made to Size
Every liner is cut and welded to your exact measurements — no folds, no guesswork.
Fully Welded, Zero Site Joins
Corners and top flanges are factory-welded to a professional standard, eliminating on-site leak risk.
Built to Outlast Your Pond
UV stable and unaffected by temperature extremes or ground movement — won't shrink or turn brittle.
Chemically Safe
No plasticisers or additives. Zero leaching — completely safe for fish, plants, and pond life.
Relaxed Fit Installation
Sits with no stress on the material, unlike stretch-to-fit alternatives — for maximum long-term life.
Repairable & Extendable
Butyl can be vulcanised or seamed with MyPond MS300, so future changes are straightforward.
Underlay is required to keep your guarantee valid
Our 260gsm geotextile underlay protects your liner from punctures, root penetration and abrasion. Skipping it at checkout will invalidate your 25-year guarantee — we strongly recommend selecting "Yes."
How ordering & installation works
Measure your pond
Take the internal length, width, depth and desired top overhang in millimetres.
Get an instant price
Enter your dimensions above and choose whether to add the protective underlay.
We weld to size
Your liner is cut and factory-welded to your exact measurements — ready in 1 week on average.
Drop in & secure
Lower the folded liner into your concrete block or timber structure, unfold, and secure the flange.
Frequently asked questions
What is a box welded pond liner?
A custom-made liner factory-cut and welded at the corners to match your pond exactly — no folds, no pleats, a clean professional finish.
Why is 1mm butyl rubber the best material for a box welded pond liner?
Butyl rubber is the gold standard for pond liners, and for good reason. It's incredibly flexible, so it moulds to the exact shape of your pond without cracking or distorting — even at the welded corners. It handles temperature extremes well, staying supple in winter and not degrading in summer UV exposure. At 1mm thickness, it's heavy-duty enough to resist punctures from roots, gravel, and general use, while remaining easy to handle during installation. It's also fully fish and plant safe, making it the go-to choice for anyone serious about their pond.
How long will a box welded butyl rubber liner last?
A quality 1mm butyl rubber liner will last 25 years when installed correctly. Butyl doesn't dry out or become brittle over time like cheaper alternatives — it holds its elasticity for the long haul. In short, install it once and forget about it.
Do I need an underlay with a box welded pond liner?
Yes — underlay is required for your guarantee to remain valid. Even though butyl rubber is tough, sharp stones, roots, or rough surfaces beneath the liner can work against it over time. An underlay acts as a protective cushion, reducing the risk of punctures and protecting your liner. It's a simple step that keeps your guarantee intact and gives you real peace of mind.
What makes a box welded liner different from a standard sheet liner?
With a traditional sheet liner, you have to fold and pleat the corners yourself to make it fit — it takes skill, patience, and you never quite get a perfect finish. Our box welded liners are different. We weld each liner in-house to the exact dimensions of your pond, so it simply drops straight in, ready to use. No folding, no pleating, no specialist knowledge needed — just a clean, neat fit every time.
Does the liner need to sit inside a structure?
Yes — the liner must sit inside a solid structure such as a timber sleeper pond, raised brick planter, or similar rigid surround. It isn't designed to hold its shape unsupported. What it does do is drop straight in and conform perfectly to your structure, giving you a completely watertight finish with no effort.
Can the liner be repaired if damaged?
Yes — butyl rubber is one of the easiest liner materials to repair. If you do get a puncture or small tear, a butyl repair patch kit bonds directly to the surface for a watertight fix. The liner must be dry and clean before applying the patch, but the repair is straightforward and can be done by any competent DIYer using MyPond MS300 pond sealant — no specialist required.