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Sealing Your Pond Print E-mail
A house is an investment for many decades. Building in ones garden, standards are usually not set quite so high. But here, too, the truth is: the longer it lasts, the less has to be done twice and hence the less expensive it ultimately is.

This is especially true for ponds, because repairing a defect sealing is usually more work than a new construction. The clear aim therefore has to be to build correctly and durably to avoid useless mud fights.
The pond is only beautiful as long as its sealing lasts. This is as important as the engine is for a car.
If it becomes crumbly, everything has to be cleared out and one starts anew, with expenses and all.

Protection from Below
The liner is usually pressed onto the ground with a load of 1-2 tons/m². In many ponds this is equivalent to two large trucks or about 50 middle class cars. Stones and rocks in the ground are the main problem here. Many opt for as thick a liner as possible, but all liners thin out when stressed and thus become more vulnerable. This can only be avoided by a good load distribution. If you forgo this, you are saving at the wrong end. 
The whole pond is only as good as its sealing. Building it on top of a layer of sand is not a good protection, because sand can be undermined, for example, by mice, plus it drains water quickly in case of damage to the liner. Fleece900 protects against stones and roots. Additionally, in case of damage it clogs up with suspended matter and closes the leak. Fleece900 has become a standard. Find out more about it here
During the production process for NaturaGart-Fleece900 500 kilometres of fibres are extremely compacted per m² of material. The combination of stress and sealing fibres gives the best security.

The Right Liner
Even low quality liners can be made in such a way that they feel like high quality to the touch. There are technical specifications for new material. But liners age, and sometimes very quickly. There is liner in the marketplace that felt great on the shelf, but that didn't survive its first winter. Saving on liner can spell massive problems: Replacing a crumbling liner takes a lot of time and at least doubles the cost for the liner.
Many liners are sold with fuzzy specifications (UV-resistant, frost resistant, etc.). Many dealers don't know a lot about their liners, because their suppliers buy them from different manufacturers abroad. NaturaGart products are branded and manufactured under strict quality assurance in Germany for NaturaGart. We have decades of experience with this.
A pond's sealing has to last! You can't see how quickly a new car will corrode. With a liner you can't 'feel' how long it will last.

Protection from Above
In many cases the risk from above is just as big as from below. This begins with the deteriorating effect of UV light from the sun and ends with horse bathing or school kid vandalism. The NaturaGart composite mat gives the liner a rock hard shell for perfect protection. We assume that such constructions last for decades, or, expressed in another way: you build it once in your life...
Protection from above is important in the following situations:
Entry areas of swimming ponds.
Stepping stones should not have direct liner contact.
Steep banks
To keep the damaging UV sunlight from deteriorating the liner.
Risk of vandalism
School ponds, public ponds and childrens' playing-ponds.
Rock decorations
In order to avoid direct contact with the liner.
If the pond is going to be built with lots of stones on top of the liner, the composite mat is recommended.

Other Options
Layers of clay in the ground are water tight because of the pressure exerted on them from the soil above. Clay quills and stops up pores because the pressure from above does not allow it to expand. Without pressure, clay will well up into the water and become liquid. Fish, ducks and swimmers swirl the layer up and the water becomes a brown-gray colour. Layers that are too thin will not be waterproof.  
To extract, transform, transport and finally construct with clay probably uses more fuel than is necessary for making a liner. Therefore, using clay is much more expensive than using a liner.Another disadvantage is the missing capillary barrier to the surrounding land. This means that clay ponds lose water. Clay was fashionable in the 80s but it hardly plays a role anymore nowadays.
A pond made with clay bricks - destroyed by moles and roots, because the layer was too thin.

Large basins have to be reinforced with structural steel and even then cracks can form so that a liner has to be installed on top of the concrete.
If you want more safety you should lay the liner underneath the concrete. You can also simply use the composite mat.
In practice concrete ponds are obsolete. The price of reinforced concrete is much higher than that of the best liners.
In the NaturaGart Scuba Park more than 3,000m³ of concrete were used on top of the liner. The concrete distributes the load rather than make the pond waterproof.
Concrete is only waterproof after it has been compacted with a vibrator. This is hardly possible on sloping banks because it is difficult to make a shuttering in these places. As a consequence shores remain unsatisfactory.

Prefabricated Ponds
These basins are normally not as strong as they look. Many are deep drawn which lets the edges seem thick and strong, but the walls tend to be much thinner, leaving thicknesses of even less than that of a 1mm liner.
On top of that the installation is difficult, because the basin has to be precisely excavated in negative form. Because this is complicated, many of these basins aren't level.
Prefabricated basins are only really used for mini ponds. They are relatively expensive and the installation is often more complicated than the customers anticipate.
Manufacturers of larger glass reinforced plastic basins had problems with cracking due to frost and settling. Some even went into receivership. The apparent durability can be had much easier and cheaper using fleece, liner and possibly composite mat. 
Prefabricated basins only have a share of the mini pond market. These basins are difficult to install.

Fibre Reinforced Plastic
Such specialty solutions haven't been able to prevail. This is due to high price and difficult processing. The ground's humidity alone is sufficient to make the curing process uncontrollable. This material can also set free styrenes for years.  
Liquid Liner
This material has been used on flat surfaces on roofs for years. On uneven pond floors, however, it is difficult to control its thickness. On top of that, the costs are far higher than the highest quality fleece+liner sealing.

The NaturaGart Concept
Use a combination of one of the NaturaGart liners with Fleece900. This ensures long term, safe sealing. The composite mat helps against loading and UV light. Materials can always be combined in such a way so as to achieve an economically sensible solution.