If you’re planning to build a pond, you might be wondering if a tarp can be used as a pond liner. Tarps are cheap, readily available, and versatile, so it’s no surprise that many people consider using them. However, despite the appeal of cost savings and convenience, using a tarp for this purpose may have issues.

What Are Tarps Made Of?

Most tarps are made from either polyethylene or polyvinyl chloride (PVC). Polyethylene tarps are lightweight and often used to cover things for weatherproofing, while PVC (Vinyl) tarps are heavier and often offer better abrasion resistance for certain situation such as wind whip. Both are typically reinforced to give them extra strength.

Why Aren’t Tarps Always Good for Pond Liners?

Most tarps aren’t the best choice for pond liners for several reasons. First off, they’re usually pretty thin, ranging from just 4 to 8 mils thick. Pond liners that need to last a moderate amount of time need to be at least 20 mils thick. Thinner tarps can be prone to tearing under certain situations, especially when they come into contact with rocks or roots.

Lighter Tarps also often don’t offer much UV resistance, so they tend to break down fairly quickly when exposed to the sun. The UV rays cause the material to become brittle and crack, leading to leaks. And speaking of leaks, some tarps have seams that aren’t waterproof, making it easier for water to seep out.

Some tarps such as the ones that are of the PVC variety, aren’t meant for aquatic life and the plasticizers used to make the product flexible can leach out over time and harm fish.

Why Use a Geomembrane Liner Instead?

Synthetic geomembrane liners, on the other hand, are specially designed to create impermeable barriers. Some of the most popular materials include Reinforced Polypropylene (RPP), High-Density Polyethylene (HDPE), and Reinforced Polyethylene (RPE). Here’s why they’re better than tarps in most cases.

RPP liners are incredibly durable, resisting punctures, tears, and UV degradation. Despite being strong, they’re still flexible enough to adapt to the shape of your pond. Plus, they offer excellent chemical resistance, making them a safe choice for fish ponds.

HDPE liners are often used for applications such as mines or landfills but if implemented correctly, they can be used for water ponds as well. They’re known for their longevity and can last up to 20 years with proper installation and care. These liners are also highly resistant to chemicals and UV rays, so they won’t degrade quickly.

RPE liners are lightweight but very strong, offering easy handling during installation. They’re reinforced to resist tearing and have minimal thermal expansion, which means fewer leaks from temperature changes.

Geomembrane liners also have the added advantage of being customizable. They can be manufactured to fit your pond’s exact size and shape, minimizing seams and reducing the chances of leaks. Plus, they’re designed to be fish-friendly and safe for all aquatic life.

Do It the Right Way

While tarps might initially seem like a good, low-cost option for pond lining, often their lack of durability, poor UV resistance, and tendency to tear make them unsuitable for the job. In contrast, synthetic geomembrane liners made of RPP, HDPE, or RPE offer superior durability, flexibility, and resistance to the elements.

Investing in a quality pond liner ensures your pond remains beautiful and functional for many years to come.

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