Underlayment isn’t required for most pond liner installations, but it is a good idea to protect the material from damage. Ponds being installed in areas with many sharp rocks or roots will definitely benefit from a full underlayment. If you have smooth soil that is perfectly supportive and no trees within hundreds of feet around the pond, you might see little to no benefit from installing underlayment. It’s up to if the pond is small and there’s little tear risk, but for larger residential and commercial ponds, underlayment is a must-have. You can’t install a layer of underlayment after putting a liner in place without a lot of work, so make the decision about using the material before setting up a new pond.
If you’re not sure if you need underlayment, see if your budget allows for it. It’s always worth upgrading to add this material if you can afford it. Using underlayment will extend the life of the line, allowing you to get many more years of enjoyment from your pond with minimal maintenance. If you want to plant trees around the pond or just let existing shade trees grow, you’ll definitely need underlayment. Since most ponds perform better with natural shade, underlayment should be added to most installations.
