Heavy-Duty Pond Underlayment, 15' x 15'

The Aquascape Heavy-Duty Pond Underlayment 15' x 15' (4.6 m x 4.6 m) provides a large square piece suited to wide circular or square pond designs where both dimensions need to reach 15 feet. The square format minimises overhang and waste compared to rectangular pieces on symmetrical pond profiles.

How to Use

Clear the excavation of sharp rocks and roots. Lay the underlayment over the prepared substrate. Conform to the pond contours. Place EPDM liner on top and fill to seat both layers. Trim excess after the liner conforms to the excavation.

Square cuts reduce waste on circular or octagonal pond profiles where rectangular pieces require more trimming. On large koi ponds where substrate preparation may leave some irregularities, the heavy-duty weight provides the liner more protection than standard underlayment. Overlap and tape any seams if combining two pieces to extend coverage further.

Ideal for large circular or square pond builds, koi pond installations over 4,000 gal (15,140 L), and wide-profile pond designs where a 15' square piece covers the floor cleanly without seaming through the centre.