Preformed ponds are ponds created with a preformed hard rubber liner. The liner increases the speed and ease of building a pond by taking guesswork out of sculpting the size and shape of the pond. These pond liners are also more durable than plastic, flexible pond liners. But occasionally, preformed liners may develop leaks due to seasonal freezing and thawing of water in the ponds or age. When leaks occur, use a patch kit to repair the liner.
Remove fish and plants from the pond and allow the water to continue leaking from the pond. When the water level stops rapidly diminishing, the pond has drained to the point of the leak.
Feel around the water line for tears, rough patches or irregularities in the liner. When you find the leak, circle it with a white piece of chalk or a white grease pencil. Drain the water well past the tear in the liner.
Scrub the liner with soap and water to clean away mud, algae or slime. The liner must be clean to patch it properly. Rough up the liner surface with a file or piece of scouring pad.
Allow the liner to dry before applying a patch. Trim a patch to the proper size to cover the tear and overlap the liner by 2 inches in all directions.
Spread the liner patch glue from the patch kit over the surface that the patch will cover. Spread the glue over one side of the patch. Allow the glue to become tacky.
Roll the patch onto the liner, pressing from the center outward. Work any air bubbles out from beneath the patch. Press the liner to the patch and hold it until the patch becomes dry.
Allow the glue to dry and cure completely before filling the pond with water.