How to avoid creases in an EPDM tarpaulin?

How do you avoid folds in an EPDM liner? You are starting a pond project and will soon be laying a liner. That is the moment you ask yourself about folds in an EPDM liner. How do you avoid these folds? How do you minimize them if it is not a custom-made EPDM liner?

While in the past, one was often content to simply lay the liner at the bottom of the pond, which caused the formation of numerous folds, nowadays the liner is installed meticulously.

How to avoid folds as easily as possible!

Folds can be avoided or limited in different ways. Everything depends on the shape of the pond, the type of membrane, and the technical knowledge of the installer. In a rectangular pond, there are generally very few folds. It is more complicated when you have a rounded shape.

For folding an EPDM liner, we recommend starting from the center if your pond has a round shape, and from the corners if it is rectangular.

Position the folds as vertically as possible. Horizontal folds can be removed by stretching the membrane, and oblique folds can often be placed more vertically. Once the pond is filled with water, the vertical folds will be barely visible, especially with a rubber liner. Limit the number of folds. It is better to make one large fold than three small folds. It is both more aesthetic and more efficient.

Preparing the installation well to limit folds

A good portion of the folding is determined before you even unroll the liner: an even bottom and a non-rushed installation make all the difference.

1. Clean the bottom. Remove stones, roots, and sharp objects, then pack down the soil. Slightly round off the corners of the tiers.
2. Lay the protective geotextile. It protects the membrane and smooths out small irregularities in the terrain.
3. Unroll in mild weather. EPDM is more flexible when it is warm: leave it in the sun for a few moments before putting it in place.
4. Center without pulling. Place the liner in the center of the pond, letting it conform to the bottom, and walk on it without shoes.
5. Fill gradually. Let the water rise in stages and adjust the folds as you go, orienting them upwards.

Still hesitating between a liner, a preformed shell, or concrete? Our comparison which product to choose for waterproofing your pond helps you decide.

I want to cut the folds of my EPDM liner to weld them

Did you know that once your fold is made, you can then camouflage it with an EPDM strip (FormFlash strip from the American brand Firestone)? You can find these strips on our online store, in the construction section, liner accessories.

If you want an optimal result and avoid the formation of folds, you can cut the excess liner in the corners of the pond. The joints are then assembled by cold vulcanization (Firestone kit for EPDM). This precision work is reserved for professionals, and you generally need to be experienced, unless you are sure of what you are doing :) An error is unforgiving.

A leak appears after installation? See our article how to repair a pond liner.

Choosing a custom-made EPDM liner

To have a custom-made EPDM liner produced, simply submit a plan with the exact dimensions of the pond. This liner will subsequently be heat-welded in the factory. This assembly is also called heat vulcanization.

It is one of the easiest solutions if you wish to avoid folds. Simply lay the protective felt and unfold the 3D EPDM liner in the pond. Installation, which is possible in less favorable weather conditions, does not necessarily require the use of a pond professional.

To request a quote, visit our page custom-made EPDM liner: simply send a detailed plan of the pond.

The envelope technique for rectangular ponds

You do not wish to purchase a custom-made liner. Here is a simple method for folding the corners of a rectangular pond; of course, there are other techniques to hide folds.

Once the banks are finished, all that remains is to hide the edge of the membrane: find all our ideas in how to hide my pond liner. For a stream in several pieces, also see overlapping two EPDM liners for a stream without leaks.

Calculating the right size of liner

A liner that is too tight will stretch and pull on the corners; a heavily oversized liner multiplies the folds. The usual calculation adds twice the maximum depth and an overlap for the banks to each dimension of the pond.

The overlap, generally around 30 to 50 cm on each side, serves to anchor the liner under the stones or soil of the bank. For tiered ponds, measure instead with a tape measure by following the profile of the hole, from edge to edge.

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