Laying, gluing and repairing pond liner

Pond liner is a special liner intended for sealing all types of ponds. You can use it to design garden ponds, but also swimming, bathing, fish and koi ponds. Films made of PVC, polyethylene or rubber are used. The film is offered in thicknesses from 0.5 to 2 mm. The thickness has an influence on the installability. The thicker the foil, the higher the weight. The thin film has fewer creases and adapts better to the surface. In addition, it is easier to cut and handle. On the other hand, the thick film is more stable and tears much less often. It lasts longer. Of course it is also a question of price. The 1mm thick film is almost twice as expensive as the 0.5mm thick.

The foil must be watertight, of course, otherwise the pond will leak. But it is also important that it is soft, tear-resistant and stretchy. So it has to be flexible. This ensures that it does not tear easily. That is why it is also important that it is frost-resistant. The film must not tear when it freezes.

The pond liner is at risk from sharp objects such as sharp stones, tree roots or similar. These must be disposed of properly. A fleece under the foil protects it additionally.
For a normal garden pond, a 1 mm thick liner is generally sufficient. Ponds that are hardly in danger of being damaged can also be designed with the thin foil, i.e. with a thickness of 0.5 mm.

Materials for pond liner

There are different pond liners. The material is very important for the ponds. Depending on the use, a material is more or less suitable. In general, dark pond liner is recommended, i.e. black or dark green. On the one hand, this is because the sunlight can warm up the water better due to the dark color, which is an advantage especially in spring and which the underwater plants and fish also like, and on the other hand, because fish feel more comfortable in the dark, i.e. not how on the salver.

PVC pond liner

• Standard pond liner
• Different colors – blue, green or black
• Can be welded with hot air or solvent welding agent
• Very flexible
• Can be laid almost wrinkle-free
• The thicker the film, the stiffer it becomes
• Easy to fix
• Cheapest variant

PE – pond liner

• Made of polyethylene
• Only suitable for ponds in the highly elastic version
• Lighter than PVC
• More environmentally friendly than PVC
• Without plasticizer
• Stiffer than PVC and therefore adapts less well to the substrate, wrinkling
• More durable than PVC
• UV-resistant
• Well suited for streams
• Harder to repair

EPDM – pond liner

• caoutchouc or rubber sheet
• High stretchability
• Very UV stable
• Very high life expectancy – up to 50 years
• The pieces are not glued or welded
• Very environmentally friendly
• Insensitive to UV light, free radicals in the air and acids
• Most expensive foil

Preparation of the pool

First, an appropriate pit with shallow and deep zones must be dug. It is ideal to spread a layer of sand about 5 cm thick on the individual zones. It offers the film additional protection for the fleece that comes over it. A ditch about 15 cm wide and deep should run around the pond, where the liner will later be attached.

Foil shy

If you want to save work and time, you can cut the film to size before laying it. It only has to be laid out and welded or glued, depending on the size. The faster you proceed, the less risk there is of the pond pit being destroyed or changing shape (rain). Speed ​​is also required when welding. Rain delays time.

Step 1

• Lay pond fleece (usually rolls)
• Weigh down the edges with sand
• Lay the foil on top of that
• Start at the top of the pond
• unroll foil
• Watch out for corners and stones

step 2

• Unfold the foil and pull it into the pond
• The fleece must not slip
• Laying direction of fleece and foil should be the same, this makes the work easier
• Alternatively, roll the foil into the pond and then pull it up and out to both edges
• Consider the necessary connections for pumps, floor drain and pipe penetrations

step 3

• Let the water in to allow the film to adjust properly
• only fill about 1/3 full
• let it sit and keep adding water
• Plant now
• fill the pond completely

Glue the pond liner

If you buy ready-made pond liner in the appropriate size, i.e. made to measure, it is welded with special industrial equipment, not glued. If you build the pond yourself, you will usually glue the connecting pieces together, not weld them. Liquid glue is used. There are special adhesives for pond liner, so not every adhesive can be used. You have to pay attention to the material your pond liner is made of. Not all adhesives are suitable for all foils, it is more the case that there is a special adhesive for each.

• Glue with tetrahydrofuran (aggressive solvent)
  • Liquifies the pond liner in the seam area
  • Both surfaces must be pressed against each other
  • Both parts connect
  • The difficulty is that this glue only sticks for seconds. Inexperienced people often have difficulties with this.
• MS polymer based adhesive
  • High initial adhesion
  • Hardens quickly
  • Permanently elastic after hardening

welding foil

With inexpensive pond liner it is often better to “weld” than to glue. A solvent welding agent is used for this, similar to an adhesive. This creates a more stable connection between the foil pieces. It is important with this type of assembly that the whole thing can dry for several hours. It is beneficial to complain about the “seam”. Due to the resulting pressure, the solvent welding agent can create a very tight connection between the two parts.

Another option is to dissolve a piece of pond liner in a container of solvent welding agent. This mass is applied to the edges of the other piece of film, like glue. This is how the individual parts are connected, i.e. by a chemical process. The individual parts practically merge with each other. With glue there is a layer between the two parts, with welding everything is tight together like a single piece.

Repair pond liner

Even with the best installation and care, it may be necessary to repeat the pond liner. Despite everything, holes and cracks can occur. As soon as you have identified a defect, you have to act.

PVC film can be easily patched, but with permanently elastic power adhesive. You simply stick a piece of foil with the adhesive on the damaged area. It is clear that the water should first be drained to such an extent that you can work well and dry and that the area is clean. The patch should be large enough that it protrudes about 15 to 20 cm on all sides. The piece of foil must be pressed firmly, preferably with a wallpaper roll. There must be no air bubbles. But if the film is more than 20 years old, it’s time to replace it, otherwise you’re mostly just busy making repairs.

It is more difficult to repair the rubber foil. A component adhesive is used for this. The foil must be very clean. Then the defective spot is treated with an adhesion promoter. It is simply applied and left to work for 10 to 15 minutes. Double-sided adhesive tape is attached to this. A piece of foil of the appropriate size is then pressed onto it and pressed firmly.

Find a leak in the pond

Inexpensive PVC films in particular tend to lose the plasticizer they contain over the years. They just escape. As a result, the films become more brittle and can sometimes tear. You can tell by the fact that the water level is constantly falling, more or less quickly depending on the size of the spot.

Only one thing helps here. First you have to find the height of the leak. To do this, the pond must be filled and observed every day. It is best to mark at one point how much water escapes each day. When the water level no longer drops drastically, you have found the level at which you have to search. Now the film has to be cleaned all around in this zone so that leaks can be better recognized. Buttons often help too. Sometimes a stone, a sharp branch or something similar lies under the foil and is responsible for the leak. You can find that out quickly with your hands.

The right disposal

Pond liner cannot simply be disposed of with the residual waste. That’s because of the ingredients. If you’re lucky, it counts as hazardous waste and can be taken to the nearest recycling center. However, there are usually costs involved, but this is regulated by the individual federal states.

Conclusion
A pond with pond liner offers a wide range of design options. Pond liner is a comparatively inexpensive option, depending on the quality and thickness of the liner. It is best to line the pond with just one piece of foil. If that doesn’t work or if repairs have to be made, there are two methods available: gluing and “welding”. Both connect, but welding is more stable. Laying out a foil is not too complicated, but you should get help. This usually doesn’t work so well alone, especially in larger ponds. It is important to work out the shape of the pond well before the liner is laid. If you need help, you should contact a professional. “Pond builders” can be found in specialty stores or on the Internet.