Pond Liner Underlay
Pond Grade Underlay - At 150 - 180g sq/m thick, this is the most common type of underlay.
Heavy Duty Underlay - At 250 - 260g sq/m thick this is the thickest underlay. Both are sold in 2 metre wide lengths and available to purchase by the metre.
Both types will create a barrier between the liner and the ground, and prolong the life of your liner. They are made from tough materials that will not rot, are weather proof and will help guard against the localised stretching of the actual liner that can happen over time.