Underlining

  • You have dug the pond profile
  • Remove any sharp stones
  • Line the hole with an underlining – geotextile. This will uphold the guarantee for the liner you use.
  • This is sold in 4 metres width and you order as many linear metres as you need.
  • Cover all shelf areas and up stands. This does not need to be laid in one continuous piece so patch some corner areas from the overlap cut from another corner – geotextile only needs to be one layer thick 

1. Geotextile underlining     2. Polyethylene liner material    3. Butyl rubber lining

Flexible liner material

  • There are many choices of flexible liner materials:
  • Butyl rubber – can be heavy to work with but stretches nicely around curves and is a dull grey/black colour and is available with a 30 year guarantee.
  • Woven polyethylene – carries a 30 year guarantee but is a cheaper initial purchase, is lighter to work with but has no stretch so requires careful folding into curves and corners
  • Reservoir liner for larger field ponds or bad terrain is made from polyester reinforced PVC and is rot proof  and root penetration proof but is also more expensive.

To calculate the size of liner needed

  • Measure the overall length, width and depth of the hole including the height of vertical upstand to the top shelf

You need to buy:

length to order = the length + twice the maximum depth + 60cms spare
width to order = the width + twice the maximum depth + 60cms spare

We recommend Fawcetts liners for geotextile underlay and pond liners: http://www.fawcettsliners.co.uk/

To fit the liner

  • Loose lay the flexible liner in the hole
  • Make sure it reaches the pond base and the each shelf in turn without stretching taut at this stage
  • Allow equal amounts of spare liner on all sides
  • Start to fill with water.
  • If possible use collected rain water but if this is not possible then use tapwater with the addition of Chlorine Guard the eco-friendly treatment for the chlorine, chloramines and heavy metals which can be in tap water which are not ideal for plants or wildlife.
  • As the water fills its weight will pull the liner into position.
  • Stop filling at every shelf level and rearrange the liner. Make sure there is sufficient for that shelf width without stretching the liner 
  • Start to pull out the creases on a curve or arrange the folds.
  • Do each shelf level in turn
  • Stop adding water before you reach the top garden level
  • With a top edging shelf the liner will finish vertically and surplus will be above the top garden level
  • Finish the folds 
  • Make sure that the ‘behind’ side of any fold is always as high as the finished water height or one low fold will forever dictate the maximum height of water your pond will hold. 

Move on to next step to trap the liner in place with edging materials