One of the great things about using pond liners is that your imagination is the only limitation. Using a pond liner is not as easy as using a prebuilt design. However, on a personal level I really enjoy ponds that are built using liners over pre-formed options. I think the main reason is I like to see what people do with them.
There are three common types of pond liners used in creating fish ponds, each with its advantages and disadvantages - preformed pond liners, flexible pond liners, and concrete pond liners.
These are the most popular and are best suited for novices looking to set up a quick and easy pond as the provide an instant setting for either an in-ground or above ground pond solution. The costs range depending upon the thickness of the material, with the thicker being the more expensive The downfall of the preformed liner is they provide very little in the way of customization, but can still be well utilized with some careful planning.
Offer the do-it yourself pond owner the ability to tailor his pond to suit his likes and to fit most any design. Flexible pond liners are bought by the roll or by standard size cut pieces, with custom cuts available at many places. They are available in different materials, with EPDM being the most popular. Similar to preformed liners, the cost of a flexible liner will range based on its thickness, with the thicker the material being more durable and thus more expensive. Also, the ground beneath the flexible liner should also be properly prepared to negate damage from rocks or other sharp objects in the ground.
The third type of common pond liner are concrete liners. These are generally the sturdiest, but also the most difficult to work with due to the labor involved in mixing and pouring cement. Concrete pond liner applications are usually best left to a professional to ensure proper installation.. Many epoxies and sealants are available for concrete liners to give them more of a smooth finish and to be used in maintenance and repair of any cracks that may form. Initially thought of as rough and unsuitable for pond fish, concrete can now be coated with fish-safe epoxy for a smooth finish.
The main determining factor with these types of pond liners is really personal preference. If you are looking for a quick solution for a simple pond, a preformed liner will be the best bet. Looking for customization at a reasonable cost, then a flexible (EPDM) liner is probably what you need. And if you have the means and are wanting a low maintenance, sturdy pond liner, then a concrete pond liner just might be your choice.