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News and articles about products used for the containment of water and the use of flexible rubber liners for many environmentally enhancing projects.

A beginners guide to box welded pond liners

Box welded pond liners are prefabricated from a flat sheet liner and tailored to fit the exact dimensions of a formal shaped pond. Butyl or Epalyn EP (EPDM) pond liner are heat welded (vulcanised) to the dimensions customers send through of their vertically sided formal shaped pond build. Box welded pond liners are the preferred choice when it comes to water containment for Koi and ornamental ponds.

Ponds of a rectangular, circular, square or “L“ shape can all be fitted with a box welded liner as can more complex vertical sided designs. Formal ponds with planting shelves, sloping bases, uneven depths or a haunch base to fit a bottom drain to Koi ponds can all be accommodated.

A formal shaped pond being fitted with a box welded pond liner

In the above photograph of a formal shaped pond, a box-welded liner has just been fitted. As you may have noticed there are no folds nor creases. The pond liner conforms to the shape of the pond with a perfect fit.

Ponds where there are folds to the pond liner have the potential to harbour debris. This can then lead to the growth of unwanted pathogens adversely affecting the quality of water and as a consequence the health of fish may suffer. It is for this reason that tailored-to-fit pond liners are the best option of water containment for ponds home to Koi carp. The snug fit makes cleaning and maintaining your pond a lot easier.

Box-welded pond liners are made with a flange or lip around the top upon which flagstone or other edging material can be placed to secure the liner in place.

When you order a customised pond liner from Russetts Developments Ltd (RDL) it will be prefabricated to your bespoke requirements using either 1.0mm EPDM rubber or 0.75mm Butyl pond liner membrane. Customers will be given a 25 year guarantee for their liner provided it is installed above a protective underlay. 

RDL import uncut sheets of EPDM rubber in rolls of 0.75mm, 0.85mm and 1.0mm thicknesses direct from SealEco International (HQ) based in Varnamo, Sweden. This product is also known under the trade name of Elastoseal.  We have chosen to name the SealEco EPDM rubber, “Epalyn EP” to distinguish it from other suppliers of the product.

This is an example of a customer drawing emailed through to us requesting a quote for a box welded pond liner. In the drawing the customer has provided all the dimensions we need - the length, width as well as the total depth together with the size of the lip required (150mm is a standard lip). 

Formal pond fitted with a box welded pond liner and flagstone edging secures the pond liner in place

We fabricate the majority of box welded pond liners from Epalyn EP rubber pond liner. It is cheaper than Butyl while providing equal to superior qualities. Epalyn EP offers the following features and benefits to ponds of all shapes and sizes: 

  • Resistant to UV rays, adverse temperatures 
  • Performs to a high standard for over 25 years
  • Available in a choice of 3 thicknesses 0.75, 0.85 and 1.0mm
  • Resists ground movement
  • Adapts to the contours of a pond

  • Doesn't leach chemicals into the water - EPDM doesn't contain any harmful additives therefor fish and wildlife safe
  • Unlike PVC, this type of pond liner doesn't change form or go brittle when exposed to extreme temperatures - withstands temperatures down to -40 degrees F and up to 150 degrees F.
  • Environmentally friendly
  • Performs slightly better than Butyl rubber pond liner and is cheaper in price - performed better on tear and tensile strength
  • Repairs easily should it puncture
  • Offers years of great service making this a very economical choice of pond liner.


We have prefabricated and installed box welded pond liners to a number of interesting and exciting projects:

  • Botanical Gardens
  • National Trust Properties
  • Private residences
  • National Heritage 
 

How to place a order for box welded pond liners


To provide you with the snug fitting box welded pond liner you require, you will need to email through a photograph of a drawing you have done showing all the dimensions of your pond design. RDL's service offers a box welded pond liner cut and welded to the exact shape of your pond for a perfect crease-free fit. 

Here is an example of a more demanding onsite project we installed a pond liner. For very complicated formal ponds we can tailor make and install box welded pond liners on site using our 1.2mm Flagon Thermoplastic Polyolefin (TPO) liner.

For more information regarding onsite bespoke pond liner installations, you can view some of the work we have done in our Bespoke Projects section.

Examples of box welded pond liners fabricated on site for various projects

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