There’s no time like the New Year for good intentions – and one which will pay dividends for many years to come is to create a garden pond. One of the first choices you’ll have to make is the type of liner to use. The material itself is a no-brainer – always use a synthetic rubber liner rather than polythene; synthetic rubbers are much tougher and longer lasting than the cheaper alternative. Today, the most commonly used material for a box welded pond liner is the robust EPDM, a synthetic rubber which is not affected by temperature extremes or by UV light and won’t perish or become brittle with age. It is also highly resistant to compressive loads and rodent attack and has greater tensile and tear strength than butyl rubber.
The next decision is whether to line your pond with a flat sheet or with a custom-made box welded pond liner. To some extent, the csion is based on the design of the pond you are planning to create. For an ornamental or regular-shaped pond your objective should always be to achieve a lining with as few folds and creases as possible, as these will trap detritus and are difficult to keep clean. Fish and vegetable waste can accumulate in these crevices and produce pathogens that can affect the quality of your water and the health of any fish. This is especially true for koi carp which are particularly susceptible to impurities in their water.
The type of liner you use – flat or box welded – will be determined by the profile of your pond. If your pond is organically-shaped with sides that slope to the bottom the only realistic option is to use a flat sheet of liner and accept that some folds and creases will be necessary to shape it to the contours of the hole you have excavated. A better option, especially if your pond is intended for fish rather than being purely decorative, is to achieve the depth you require by having vertical drops. These can be stepped in stages to reach the depth you need. Sloping bottoms can be incorporated so long as the slope is consistent. The advantage of vertical sides is that dead material won’t get trapped and will fall to the bottom where it can be vacuumed up or where it will slide down a gentle slope towards a bottom drain.
Using a box welded pond liner doesn’t mean you have to have a square pond. A combination of rounded and square shapes can be combined. Think about each element of the liner and how it will fit together. A circular or oval pond, for example, will have three main elements – a horizontal perimeter which will lie around the edge of the pond, the vertical side, which would be made from a single strip wrapped around the wall of the pond, and the base. So long as a side panel or base, planting shelf or a perimeter can be made from a flat piece of liner without folding or creasing, then your design should be possible.
Our team has many years’ experience building box welded pond liners which are cut and welded to the exact shape of your pond and is always available to give advice on what can be achieved. You see some examples on our website. The EPDM material we use is Epalyn EP, which is particularly suited to the vulcanisation process used to bond the elements of a liner together and carries a lifetime guarantee on liners up to 100m2.