HEISSNER Pond Underlay

For biotopes, garden ponds and compact fish ponds

A pond underlay effectively protects the pond liner from damage caused by stones, roots, and uneven surfaces. Serving as a base layer in pond construction, a HEISSNER pond underlay enhances the stability and longevity of garden ponds, koi ponds, and biotopes. Made from tear-resistant material, these pond underlays are designed for permanent outdoor use and are compatible with both PVC and EPDM pond liners.

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Pond Underlay: 7 items

Which pond underlay should you choose?
The right option depends primarily on pond size, the ground conditions and required material thickness:

  • 200 g/m² · 1.0 mm thickness - suitable for smaller garden ponds with a level, sandy base
  • 200 g/m² · 3.0 mm thickness - recommended for stony subsoil, larger ponds or koi ponds

Selecting the appropriate thickness ensures reliable protection for the pond liner and creates a stable, long-lasting pond structure.

How long does a pond underlay last?
A pond underlay is designed for permanent outdoor installation:

  • rot-resistant, water-resistant and frost-resistant
  • when properly installed, it remains fully functional for 10–20 years or more

A carefully prepared, level base enhances its protective performance and further extends its service life.