Pond Liners

Pond Liner Calculator

Working out just how much pond liner you'll need to cover your garden pond is a daunting task, but thanks to our handy pond liner calculator you can easily find the right size pond liner for your needs. This pond liner calculator will tell you what size pond liner and pond liner underlay you'll need for your garden pond. Simply enter your pond length, pond depth, and pond width into the pond liner calculator and it'll do the rest of the hard work for you. Don't worry too much about taking exact length, depth, and width measurements, approximate measurements are fine. It's always a good idea to buy slightly more pond liner than you need, rather than an exact size, to make sure you have enough pond liner to cover any hard-to-reach areas of your pond that you may have measured incorrectly.

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Help and advice on shopping for: Pond Liners

Pond Liners: The Ideal Foundations For Garden Ponds

When it comes to making a garden pond, there’s nothing more important than a pond liner. These essential pieces of equipment form the very foundation of your pond, lining a pre-dug hole with a durable yet flexible material that’s designed to keep dirt out and water in.

We stock a wide range of garden pond liners here at Swell UK, suitable for all types of garden ponds from small wildlife ponds to large Koi ponds. This range includes a varied selection of products from some top brands in the pond keeping hobby, such as Gordon Low, as well as our own outstanding range.

black pond liner installed in a garden pond

What are pond liners?

A pond liner is layer of impermeable material designed to form a barrier between the ground around a pond and the water inside. They’re made using a high-pressure, high-heat process that results in an elastic and chemically stable product. This is what makes pond liners easy to install and safe for housing fish and other aquatic life. There are many sizes of garden pond liners to choose from, from small pond liners suitable for tiny nature-style ponds, to big pond liners suitable for large ornamental ponds full of fish, like Koi ponds.

What are pond liners made of?

Just as they vary in size, pond liners vary in materials too. There are several different types of garden pond liners out there: HDPE pond liners, PVC pond liners, and EPDM pond liners, including rubber pond liners and butyl rubber pond liners.

HDPE pond liners

HDPE, or high-density polyethylene, is one of the most popular pond liner materials. It’s very UV resistant and performs well in cold temperatures, making it a great choice of pond liner material for areas with unpredictable weather conditions. It’s also resistant to a wide range of chemicals, so much so that they’re often used in landfills and chemical containment sites.

PVC pond liners

PVC, or polyvinyl chloride, is commonly associated with pipes and plumbing, but it’s also a popular pond liner material. It’s one of, if not the cheapest pond liner material available. It’s very flexible too and can conform snugly in tight corners and crevices, making it a great choice for nature-style ponds with lots of nooks and crannies.

EPDM pond liners

EPDM, or ethylene propylene diene monomer, is a synthetic rubber material. Ethylene propylene diene monomer is durable yet supple, making for garden pond liners that are not only incredibly easy to install, but built to stand the test of time too. EPDM doesn’t expand or contract at high/low temperatures either, so temperature differences won’t cause it to lose its grip on your ground’s surface. Despite their softness, EPDM rubber pond liners are resistant to punctures, UV rays, and general wear and tear.

EPDM isn’t the only type of synthetic rubber material used in some fish pond liners, there’s butyl too. For a long time, butyl rubber pond liners were the most widely used type of pond liners in the UK, thanks to their highly flexible, easy-to-mould nature. That said, butyl rubber pond liners aren’t quite as durable as EPDM rubber pond liners and are a little more prone to rips and punctures.

What size pond liner do I need?

Selecting the right pond liner for your garden pond is usually quite tough, but with our handy pond liner calculator tool it's made quick and easy. Just measure your pond's length, width, and depth, and input the details into the calculator.

large garden pond full of goldfish

After a speedy calculation, the calculator will tell you how much pond water your pond will hold and the minimum size pond liner you'll need to sufficiently cover the base of your garden pond, whether that be for a small pond or a large pond, a raised pond or a ground-level pond. It'll also tell you the minimum size protective underlay you'll need.

What is protective underlay and do I need it?

A pond liner is only as good as the protective underlay that lies underneath it. This pond underlay, often some form of geotextile fabric, acts as a barrier between the ground around your pond and your pond liner. It protects the pond liner from being punctured or scratched by sharp stones or twigs buried in the ground, and also prevents your pond liner from shifting due to any ground movement. They act as a layer of insulation too.

Some garden pond liners are more durable than others, as discussed above, but no matter what type you have, you should always partner your pond liner with a layer of pond underlay. Like pond liners, protective underlay is also available in a variety of sizes and types. Here at Swell UK we stock two types of protective underlay, heavy duty protective underlay or standard protective underlay, and both are available in sizes to fit our pond liners.

We also stock pond liner edging. This is primarily a decorative product, rather than a protective one, but it does help to cover up the edges of your pond liner and shield them from damaging UV rays and other atmospheric agents, like frost.

What does the guarantee on Swell UK pond liners cover?

A lot of our fish pond liners come with guarantees, ranging from 25-years to lifetime guarantees (these guarantees are stated in the descriptions of specific products). These guarantees cover your pond liners from UV damage one of the main causes of pond liner degradation. All of our pond liners are UV resistant, but these guarantees help to give you, the pond owner, that extra piece of mind.

pond liners are UV and frost resistant

It’s important to note, however, that these guarantees don’t cover your pond liner from punctures. This in mind, it’s recommended that you purchase a puncture-resistant layer of protective underlay to sit underneath your pond liner and protect it from any rough rocks.

What pond liner do I need?

There’s a lot of variety when it comes to pond liners and picking the type that will work best for you and your pond is a difficult task! That said, there’s a lot of information here to get you started, plus a handy pond liner calculator tool at the top of the page. This pond liner calculator tool will let you know whether you should be shopping for small pond liners or large pond liners. For more advice, check out our FAQ on pond liners and useful help guides on pond building.