Book SectionsTable of Contents
The Problem Puddle Power Frog-Friendly Backyard Why are we concerned about amphibians?
Wetlands - function/type Wetland issues
How to help amphibians
Community Green Plans
Flexible pond liners
Size of your flexible liner
It is best to decide on the type of liner you wish to buy and see what sizes it comes in before you decide on the shape and size of your pond. A number of bulk liner rolls come in increments of 1.5 m starting at the 3 m width. If a homeowner has dug a pond and needs a 4x7 liner, he/she would have to buy a 4.5x7 m or 7.5x4 m liner according to the above widths.
Measure the length and width of the rectangle that your
pool fits in. Add twice the maximum depth of your pond and a
metre to each of these measurements and you have the size of
the liner you need.
1 + ( 2 X maximum depth) + length = length of liner in metres
Types of Flexible Pond liners
There are generally four types of flexible pond liners: 40 -80 mil PVC sheeting, rubberized pool liners, 45 mil High Density Polyethylene (HDPE) liners, and, our recommendation, 45 mil Ethylene Propylene Diene Monomer (EPDM) liner. Most of these liners are manufactured in black and natural tones of brown and green creating a more natural look for your pond.
Putting in Flexible Pond Liners
Before placing the pond liner you should remove all sharp objects and make sure the soil is packed down hard and level. Once a pond is put in, the bottom should be covered with 2-10 cm of washed sand topped with a layer of gravel.
When you build your pond try to pick a sunny day with no rain in the forecast for a couple of days. Sun makes digging more fun, but also warms up the liner making it a little more malleable. Do not leave your liner out on the grass in the sun, because the heat generated by the liner can kill large areas of grass. Before installing a flexible liner you should check it for manufacturing defects (holes and weak points), and line the pond excavation with 5 cm of sand or a geotextile layer. It is not recommended to use old carpet or newspapers as carpet bulks up in the corners and makes for difficult and unsightly folds in the liner, and newspaper has the potential to get soggy and become penetrable to sticks or rocks.
It is advisable to have four people to help you place your flexible pond liner. Each person can take a corner and make sure the liner is equal at all areas over the pond. A flexible liner is installed by placing it over the hole and it is held firmly with either a line of bricks or paving stones. Place a garden hose in the middle of the pond and fill with water. The weight of the water settles the liner to the shape of the pool. When the pool is filling with water, someone should be in it with their shoes and socks off helping the liner fold in the corners. They should also insure that the liner is not being pulled down unevenly which can create a potential leak when the pond is filled up to level. There is no danger of the liner snapping back under water when the weight is off because it is kept firmly in place by water pressure. This is the time to make final adjustments such as levelling the liner edge or to direct overflow to the intended area. Tuck the edge of the liner under 15 cm of soil or keep it hidden underneath stones.
We have been advised that if some flex is left in the liner after installation, the liner has less tendency to rip and allows you to work in the pool.
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