Selecting the Best Pond Liner?

You have decided to build a pond and now you need to select the best pond liner. There are numerous choices out there, at various price points. In this post I will compare your options and make a recommendation for the best pond liner.

Hard Shell Pond Liner vs Flexible Pond Liner

Pond liners can be broken into two groups; hard shell (preformed) and flexible (soft shell).

Hard shell pond liners are made from plastic in a preformed mold. They are a strong liner that is puncture resistant and will last a long time. They are a good choice for a small pond, especially if this is your first pond and you want to keep things simple.

Hard Shell Pond Liner – The Pros:

• Simple to install.
• You can see the exact shape of the final pond before you buy it.

Hard Shell Pond Liner – The Cons:

• Limited number of designs at most retailers.
• Not suitable for very big ponds.
• Large liners can be difficult to transport.
• Most have limited planting shelves which are needed if you are making a natural pond.

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Flexible pond liners are made from soft, flexible material that can easily be folded or rolled up. They are almost as easy to use as a hard shell liner and give you unlimited design possibilities. This is the type selected by serious pond enthusiasts.

Flexible Pond Liner – The Pros

• Unlimited design options since they can be formed into almost any shape.
• Easier to transport, although the liners are heavy.
• Easily add planting shelves to the pond.
• Pieces of liner can be joined together for very large ponds.

Flexible Pond Liner – The Cons

• Slightly more work to install.
• Best installed with an underlayment material to help prevent punctures.

The Best Flexible Pond Liner

There are numerous choices for a flexible liner. The following discussion will help you select the best pond liner.

EPDM Rubber Pond Liner

This has been the most common material used by both hobbyists and commercial installers. EPDM rubber (ethylene propylene diene monomer) stays flexible and is resistant to the elements for a very long time. It is not attacked by microbes in underground installations and it remains flexible in cold environments. EDPM is rated down to -45 C.

It is fish safe and is even rated for potable water use. Plant roots will not penetrate the material which is guaranteed for 20 years.

Punctures are easily repaired by the homeowner and the process is similar to fixing a bicycle tire. EPDM is less puncture resistant than PVC or RPE.

A 45 mil (1.15 mm) thickness is used for ponds. Most of the available pond liner is made by Firestone, so there is a level of confidence in the quality.

Butyl rubber pond liners can also be used, but they have become very expensive and are no longer popular.

HDPE Thermoplastic Pond Liner

HDPE (high density polyethylene) is a semicrystaline plastic that is designed for the elements, but with age it shows stress cracking in extreme thermal situations, especially along seams. The material is not as flexible as rubber, especially at cold temperatures. It is however suitable for cold climates.

HDPE is suitable for aquatic life and plants.

Fixing punctures requires an experienced contractor. The material used for ponds is 60 mil (1.5 mm)

RPE Reinforced Polyethylene Pond Liners

RPE pond liners are made with sheets of polyethylene sandwiched over a reinforcing material. This design produces a very puncture resistant liner that is much thinner than EPDM or PVC. Being thinner, they are also weigh less, making installation easier. They are not as flexible as rubber but they can form nice folds around corners.

RPE pond liners are usually installed without an underlayment, making installation a bit easier and less expensive. It can be welded together using heat.

The 30 or 40 mil thickness is commonly used. Not all brands contain a UV stabilizer.

You can also get polyethylene pond liners that are not reinforced. They really are not a good option for ponds since they tend to be very stiff, and puncture more easily than RPE.

PVC – Polyvinyl Chloride Pond Liners

This pond liner is generally the least expensive choice. It’s weight and puncture resistance is midway between RPE and EDPM. This is not a good choice for cold climates since it might crack along folds in winter.

PVC sold for ponds may or may not include a stabilizer. Without it they are less resistant to sun light. They are fish and plant safe, if the product is specifically made for ponds. Other types of PVC can contain chemicals toxic to fish.

The PVC pond liner is easy to install and should have an underlayment. It can be seemed into large sheets using tape which is easily done by the homeowner.

The 40-80 mil PVC liners with ultraviolet inhibitors have a lifespan of 10 years or more. There are many manufacturers so you need to be very careful to select a high quality product.

The Best Pond Liner

If you are the type of person who wants a product that has stood the test of time, go with EPDM rubber. Most home ponds are made from this material and they usually last 30 years. It is what I used in my ponds.

If you are willing to try a newer product, go for a high end RPE pond liner. It should last just as long as rubber, and it is much more puncture resistant. You might have trouble finding it at your local stores since it is not as popular. Based on the data for the product, it will probably become the new standard in pond liners.

Building Natural Ponds

If you are interested in natural ponds why not join our special Facebook group Building Natural Ponds. Please join the group at https://www.facebook.com/groups/1760349757565562/

More Articles About Ponds

Winterizing Ponds and Water Features

Beneficial Pond Bacteria – A Waste of Money

Pond Pumps and Pond Filters

Aquaponics – Grow Vegetables in Your Pond

Water Lilies

References:

1. What’s the Best Material for Pond Liners?; https://www.btlliners.com/best-material-for-pond-liners/
2. EPDM and HDPE Comparative; https://www.rockaroundtheblock.com.au/downloads/dl/file/id/26/epdm_hdpe_comparative.pdf
3. Image Source; https://commons.wikimedia.org/wiki/File:IMG_7540_vijver_Delden.jpg
4. Image of hard shell liner; Andy Roberts