How to install a pond liner for an in-ground fish pond

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Have you decided to go for an unusual shape or larger pond ... then EPDM pond liner is your perfect choice. Find the right place, measure the right size and the rest is easy. Depth of pond can be important and do not forget shelves for the garden pond plants and water lilies. Use a spirit level for accuracy

Installing A Liner Pond ... Towards the end of this book I will cover installing ponds in non-ideal situations. For the moment we are working on level ground and below ground. A golden rule described earlier is to use a spirit level as shown in the sketch below. Do take trouble here.

preparing garden liner pond

Step 1 dig down to the first shelf level


Step 2 if you need a second shelf then dig down to this level allowing an adequate width for the shelf (must be able to hold the plant pots you will use and function of pond size)

Step 3 dig out the centre until you reach the desired depth. You will be adding an underlay to protect your liner from stones and sharp objects so make the excavations of the shelves and centre depth some 2 inches or 5 cms more to allow for a layer of sand.

Step 4 once you are happy with excavations place layer of clean damp sand to cover complete excavation. Buy some underlay designed for ponds or use some similar material to lie on top of the sand. This is an extra protection for your liner you do not want leaks later. Some people use wet newspapers as the underlay or old carpet.


Step 5 smooth the liner out as well as possible. Place heavy stones around the edge to keep the liner in its place as you fill with water.

How to measure liner size

pond liner sizes

EPDM rubber is probably the best

Measuring pond liner size .....

  • You need to know the width of the final pond at its widest point and add at the very least 60 cm for edging.

  • You must then also add the depth and the depth again. For example if you want a pond 2 metres wide and 1 metre deep the width of liner will be 2+1+1+0.6 (for edging) = 4.6 metres.

  • For the length repeat this process. For example if you want the above pond to be 3 metres long then the length of the liner must be 3+1+1+0.6 (for edging) = 5.6 metres.

  • The complete specification for the liner must be 5.6 metres by 4.6 metres. Do not forget to allow for the edging.

smoothing pond liner

If you find the liner is stretching too much as you fill with water (it becomes thinner as it stretches) release some of the material under the stones. As the pond fills move around the edges tidying up the pleats as much as you can. Stop filling short of the edging area especially if you intend to use an edge for planting as in following sketches.

Step 6 Edging; leave for about a week before starting to allow final settling to take place. You can use SMOOTH rocks for edging as shown (please take care to ensure edge of the liner itself points UPWARDS to prevent siphoning when pond is at high level (after rain for example). Tip take soil from underneath the liner to allow each stone to fit snugly.

stones for pond liner edges

Smooth stones for pond liner edging

Plant the pond liner edges as shown here



paved pond liner edges

Or use conventional edging materials


Ensure the edging overlaps the pond by about 2 inches (to keep the liner in the shade to prevent sunlight degradation). Once again note that liner points up to prevent siphoning.

This web page is an extract from Tony Roocroft's "The Complete Pond Solver" ... you can read more about it at

How to install a preformed garden fish pond liner in ground

How to install EPDM pond liners in ground or above ground ponds

How to Make a Small Pond Filter Bigger ... It's Easy.

How to Work Out the Right Pond Liner Size

Improve your garden fish pond create a nighttime mood and

Installing EPDM fish pond liner