Repairing pond liner : this is how it works

Repairing pond liner

If your pond suddenly loses a lot of water, it’s time to repair the pond liner. Here you can find out which sources of error you should consider before digging out the whole pond to use a new liner.

If your pond loses water, it doesn’t necessarily have to be a hole in the pond liner. There are several weak spots on the pond that are more likely.

Especially in summer, due to the evaporation and transpiration of plants, a daily water loss of around 10 cm is expected. Fountains or streams can also be responsible for water losses – especially on windy days.

Here the wind carries the water drop by drop into the edge area or out of the pond. If this goes on throughout the day, several liters can be “lost” in this way.

In addition, decorative materials such as sea mats, plant bags and stone foil are the main culprits for water loss, generally, anything that could have a capillary effect. 

In such cases, the materials pull the water out of the pond like a wick; if the materials do not end within the foil seal, the water sucked in does not get back into the pond. 

Connections, for example, between the pump and filter or the watercourse, pose an additional risk if these connections are no longer tight or have not been put together professionally from the start.

Some of the water can seep into the ground without being noticed.

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Hole in the foil

If all other possibilities have been checked and it has not been shown where the water loss could otherwise originate from, one must assume a hole in the pond liner.

It is usually relatively time-consuming and time-consuming to find the defective area. After all, not all ponds are as empty as a classic koi fish pond. Due to plants, stones and soil, clearing the pond is sometimes more work than creating the pond beforehand.

Therefore, you should proceed prudently and first localize the hole. To do this, fill the pond to the brim and mark the water level with a chalk line every day.

When the level stops falling, the water depth is where the hole is. Now all you have to do is look for the hole in the area between the water level and the previous day’s markings.

Old rags and your own hands are particularly helpful: You can often feel the suspicious spot because mostly sharp stones, shards or plant roots are responsible for such holes.

Remember, if the water sinks too deep and the hole is too deep, you will need to relocate your fish.

General information on repairs

Once you have found the hole, you have to repair the pond liner. But this only makes sense if the pond liner is not too old.

It is the case when it is severely hardened and has lost its flexibility. Repairing with a patch is only worthwhile if the film is still flexible enough.

If it is no longer that, you should think about a complete replacement, as in such cases, the next hole in the foil is preprogrammed.

If the film proves to be flexible enough, you can find the repair materials you need. In such cases, it is advantageous to keep some foil back when building the pond.

So you have a patch that fits the foil perfectly. By the way, when laying the film, you should make sure that you work as wrinkle-free as possible because the first thing that the film is brittle is any wrinkles.

When you have located the hole, the water must be drained off to work dry.

The prerequisite for repairing the pond liner is, by the way, that the area in question has been thoroughly cleaned of deposits, algae and dirt; otherwise, the glue won’t work as it should.

In addition, water should only be allowed to return to the pond after it has hardened for 48 hours.

Repairing pond liner: very easy

PVC pond liners are relatively easy to mend. All you need is PVC pond liner adhesive and a patch to patch.

As already mentioned, this piece of the pond liner must match the quality and thickness, and if the color is the same, the repair will be more or less invisible afterwards.

The unique adhesive is a permanently elastic power adhesive with a high initial adhesive strength (this process is also called “cold welding”). Now only the glue is applied according to the instructions, and the patch (overlapping around 15 to 20 cm) is pressed on.

Repairing rubber foils (EPDM), on the other hand, is a little more complicated: several adhesives are required here. It is also essential that the film is processed with a unique basic cleaner.

Then an adhesion promoter is applied to the dry rubber film. Later on, this primer is followed by double-sided, permanently elastic tape, which is especially suitable for bonding EPDM.

The film patch, which you must press off hard, is now placed on this adhesive point. It will work ideally with a wallpaper roller.

Finally, there is still the repair with liquid pond liner based on polyurethane, which adheres to almost all surfaces. For this reason, it is ideal for mending pond liners, but not with PE liners.

The liquid foil is applied over the holes with a protrusion of around 20 cm in two to three layers. If the hole in the foil gapes, fix the place with duct tape and rub over it.

The film should dry thoroughly between the individual layers so that the individual layers become stable. It strengthens the spot and prevents new holes.

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