Installing an Oversized Pond Liner: Techniques for a 17x20 ft Liner in an 8x6x4 ft Pond

A pond 8x6x4 ft was sold a 17x20 ft liner. The owner asks about installation, whether to remove the old liner, and using seam tape.

Liner Sizing

17x20 ft is correct for an 8x6x4 ft pond (length + 2x depth + 2 ft overlap = 8+8+2=18; width + 2x depth + 2 = 6+8+2=16). The extra allows for shelves, folds, and secure edging.

Installation Best Practices

• Keep old liner: Acts as protective underlayment.
• Don’t seam below waterline: Seam tape fails under constant pressure. Only use above water (e.g., waterfall connection).
• Lay loosely: Allow folds to settle; don’t stretch tight.
• Edge coping: Secure liner over the rim with rocks, pavers, or coping stones.

Waterfall Connection

Use Savio’s waterfall foam and proper liner-to-plumbing seals. Watch Savio’s online video for technique. Seam tape is acceptable only above the permanent water level.