Lining Your New Pond

So you’ve decided to install a pond? Congratulations! Ponds make a wonderful addition to almost any area and can become the relaxing hero space you never knew you needed. Before getting started you would have gone through a planning process and formed an idea of how big you wanted your pond to be but now the hole is dug and you’re ready to start construction, it’s time to measure out your actual dimensions so you know exactly what you’re working with.

This will give you a general idea of what kind of equipment you’ll be wanting to use moving forward and allows you to make any desired alterations with fewer consequences than you would have further along in the process.

If you’re happy with your shape and dimensions, it’s time to move on to the underlay.

Pond Underlay

While some may suggest simply laying down sand, old carpet or even newspaper before lining your hole, sand isn’t capable of protecting the walls of your pond and will shift with the rest of the ground and carpet and newspaper will rot over time. Plus, all of these options require substantial amounts to be used if you’re serious about protecting your EPDM liner. For best results and longevity, we firmly believe that a proper pond underlay is the best choice.

It may seem excessive to put down a ‘liner’ for your liner but a quality underlay has many benefits for your pond and EPDM liner including:
  • Providing protection against rocks and other puncture creating objects. EPDM liner is tough, but it isn’t superman.
  • Helping prevent any shifting of your EPDM liner that may occur as a result of ground movement.
  • Defending against intrusive roots.
  • Increasing the longevity of your EPDM liner.
  • Adding a barrier between your EPDM liner and any rodents or other burrowing creatures that may try to find their way into your pond.
  • Any leftover underlay can be used as a protective overlay within your pond if desired to help keep pebbles and plant pots in place.
  • Leftover underlay can also be used to help anchor plants in certain instances as they will find it easier to grip than the EPDM liner.

To calculate how much underlay you’re going to need, you can get a piece of string or other flexible object and lay it in the hole. Make sure you do this across both the longest and widest points of your pond and factor in a 300-500mm overhang for best results. The same measurements can be used when determining how much EPDM liner you will require. Store these measurements somewhere you can easily access them again in case you need them in future.

If your pond requires underlay longer or wider than you can purchase, ensure that the overlap is substantial enough that installing your EPDM liner will not cause the underlay to shift apart and leave bare earth. This provides the best protection and also reduces the chances of your liner ending up on bare earth when the ground shifts.

Follow the same principle when confirming measurements for your EPDM liner if necessary.

In preparation for the arrival of your underlay, ensure that there aren’t any jagged edges or sharp objects within the hole and smooth out the walls and floor to enable easier installation.

Once your underlay arrives, you can lay it out and use rocks, tent pegs or another suitable backyard object to weigh it down and prevent large movements.

Pond Liner

EPDM Liners are durable and flexible making them ideal for pond construction.

If a single piece of liner is sufficient for lining your entire pond this part of the process will be far simpler than if it isn’t but that doesn’t mean it is impossible to use multiple sheets.

If your pond can be lined with a single sheet, simply lay your liner in the hole ensuring that it conforms to any curves and shelves within your pond and sits flush across all areas of your hole. You can use the same tent pegs or rocks that you used for your pond underlay to hold the EPDM liner in place until you are ready to start filling your pond.

If, however, your pond is particularly large or an odd shape, it may be necessary to use more than one liner sheet. In this instance, you will want to work from one side of the pond across, joining and sealing your liner as you go.

As the liner is what keeps your pond watertight it is advisable to use a specially designed pond liner joining tape. Said tape is double sided butyl adhesive which is the easiest way to confidently join your liner and keep everything nicely sealed.

Note that when using a pond liner joining tape, your liner must first be scuffed with a scrubbing tool then coated with primer to set off the chemical bonding process. For best results we suggest rolling over your join with a seam rolling tool and applying a pond liner cover strip for extra protection.

Once all pieces of liner are securely joined you can weigh your liner down using the same method you used for your pond underlay.

Now it’s time to start filling your pond. Don’t worry if your liner isn’t sitting perfectly yet, as the incoming water settles it’ll weigh down the liner allowing you to smooth out any wrinkles that may appear and smooth your liner into the exact position that you want it in.

Note that you will need to perform this step while your pond is still filling up as once it is full, a correctly installed pond underlay and EPDM liner will be incredibly difficult if not impossible to reposition.

Once your pond is full, you can trim off any excess underlay and liner if desired, just ensure you keep your 300-500mm overhang. Any trimmed excess can be used to line waterfalls or other design elements that need to be kept watertight or as extra protection underneath heavy additions to your pond.

If you’d rather not add the extra step of trimming your liner and underlay, you can simply disguise or cover them when you landscape around your pond.

If you have any further questions or would like assistance with planning, constructing or maintaining your new pond, please do not hesitate to get in touch via our contact page or by calling us on 1300 005 670. Our friendly team of experts are always happy to have a chat and want to ensure that you get the best experience possible and love your pond.