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- Thick 0.35mm HDPE pond liner with underlay
- Supple, UV resistant and 40-year guarantee
- Available in a wide variety of sizes

Palletised delivery
Large sizes may be delivered on a pallet for protection in transit.
A high-quality product that is very easy to fit. My pond is now very watertight.
What is the Swell HDPE Pond Liner 40-Year With Heavy Underlay?
The most popular Swell UK pond liner teamed up with the most popular Swell UK underlay, the Swell HDPE Pond Liner 40-Year Guarantee has everything you need to protect your pond from punctures and leaks. This pond liner has been made from 0.35mm-thick UV-resistant HDPE (high-density polythene) that is both durable and supple for easy installation and long-lasting results. In fact, the HDPE pond liner is so durable that we sell it with a pond liner 40-year guarantee against UV damage. This pond liner comes in a wide range of sizes to suit everything from small wildlife ponds to massive Koi ponds.
How difficult is it to fit this pond liner?
UV-resistant HDPE pond liners are quite supple, making installation easy. While they have little flexibility, they should mould to the shape of most fish pools, fountains and ponds with ease. It's key that you make use of the free underlay, as only an appropriate underlay can keep your pond liner protected from the earth beneath while you work with it in your pond.
How much pond liner should I buy for my pond?
Our Pond Liner Calculator will help you determine the right length and width of liner for your pond. Finding the right size pond liner is key, as a pond liner that is too small is ineffective and a pond liner that is too large is wasteful. We'll even match the size of your HDPE pond liner with an appropriate pond liner underlay, so there's no need to worry about matching your pond liner and underlay for ultimate pond protection.
What does the guarantee cover?
This Swell HDPE Pond Liner With Swell Pond Liner Underlay carries a 40-year guarantee, but we also have other variations with lifetime guarantees. As with every pond liner sold in the UK, the guarantee covers UV damage only, not punctures.
Features
Material | HDPE |
Thickness | 0.35mm |
Colour | Black |
Liner suppleness | Very |
Liner stretchiness | No stretch |
UV resistant | Yes |
Guarantee | 40 years |
Underlay included | Yes |
Underlay type | Swell Pond Liner Heavy Duty Underlay |
Underlay thickness | 80gsm |
Underlay colour | White |
Pond sizes | Small-large |
Koi window compatibility | Not suitable |
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