Pond liners are generally ordered directly in the required dimensions, and the manufacturer already welds them together to this size. In this article you can read how to determine the correct dimensions and calculate the required size of the pond liner, and what needs to be considered.
It is annoying when too much or too little pond liner is bought
Basic Measurements
The three basic measurements that play a role in a garden pond are:
- length
- width and
- depth of the pond
The later intended use should also be taken into account during the planning phase.
Example fish pond
For example, ponds with fish should always be at least 1 m deep. In addition, the fish that you want to accommodate in it should also have enough space. The amount of space required depends on the fish species.
Of course, koi, which can often reach a considerable body length of up to 80 cm, also need sufficient space in the pond. If, on the other hand, you use the easy-to-care-for molderies, which are only 9 cm long and like to move in swarms of around 15 animals, you need a little less space (but still enough so that the fish can gather in the swarm appropriate to the species).
In this case, find out beforehand what dimensions your pond should have and plan accordingly. The size of the pond liner then results from the dimensions of the pond.
Detail measurements for the slide
A pond is not the same depth in all places, but has an embankment on each side. In order to take this fact into account, you have to calculate a little more precisely. We show this with a small example.
the maximum length of our garden pond should be 5 m. the maximum width (at the widest point) should be 4 m. At the deepest point our pond should be 1.50 meters deep.
Now the following formulas are used:
Slide Length = Maximum Length + 2 x Maximum Depth + Overlap
Slide Width = Maximum Width + 2 x Maximum Depth + Overlap
You can always calculate around 80 cm as an overlap. This means that peripheral development and capillary barriers are already well taken into account.
This results in the following required liner size for our pond dimensions:
5 m + (2 x 1.50 m) + 0.8 m = 8.80 m as foil length
4 m + (2 x 1.50 m) + 0.8 m = 7.80 m as film width
Be aware that this calculation is only an approximation. Above all, the embankment sections are recorded here only very imprecisely.
measure details
If you want to have very exact lengths and widths of your liner, you can also easily measure your pond:
Place a tape measure across the embankment and throughout the pond, also taking into account the capillary barrier on either side. Your tape measure will give you a very accurate guide to how long and wide your slide needs to be.
grid dimensions
You can also create a grid plan to calculate the foil requirement more precisely, especially for irregularly shaped ponds. This helps you to estimate the need for liner reasonably well even where the length or width of the pond varies.
When determining the grid dimensions, an imaginary center line is simply drawn through the pond. The width of the pond in this section is then measured at regular intervals starting from the center line to the left and right and entered on the plan as a grid width.
Especially in the case of irregularly shaped ponds, this helps to get an idea of how much liner you actually need and how wide at which point the pond is. When measuring, do not forget to take into account the length of foil required for the edge design at each measuring point (at least 50 cm on each side, a little more is better).
As a measuring distance you should best based on the width of a film web offered by the manufacturer. This helps the manufacturer to proceed in a planned manner when producing the film and welding the films together. Do not forget to mark the position of the center line on your grid plan and to label the distances left and right separately!
Grid Slide Limitations
You should remember that foils that are made for you in grid dimensions can no longer be complained to the manufacturer later.
In addition, these liners often come with a small surcharge (usually around 10%) on top of the actual price per square meter for the garden pond liner. They are always a bit more expensive due to the grid dimension order. In most cases, however, this pays off due to the lower waste compared to a rectangular film, which you do not have to pay for in this case.
Complex pitches
With ponds, it can happen that the side walls do not rise evenly, but are laid out in the form of terraces. Creating a so-called shore terrace is recommended for most ponds anyway.
In order to also take these dimensions into account, you can expand your grid plan accordingly. Mark the width of each terrace on it and indicate the corresponding depth for each section. In this way, the foil can be calculated more precisely, since you need a little more foil width and length than with a normal sloping embankment.
tips
In the case of very complicated pond shapes with several terraces, to be on the safe side, you should leave the calculation to the manufacturer, who has more experience with it. Ask if you can simply hand over the pond sketch.