Outdoor tarps are supposed to make life easier — until one tears at the corner, leaks after a storm, or blows halfway across the yard. If this sounds familiar, the problem usually isn't bad luck. It's a mismatch between the tarp you bought and the job it was asked to do.
This guide explains the three most common tarp failure modes, how to prevent each one, and how to pick the right heavy-duty waterproof tarp for your specific outdoor setup.
Why Outdoor Tarps Tear
Tearing almost always starts at the points of highest stress: corners, edges, and grommets. When a tarp is pulled too tightly — or is simply too thin for the load — pressure concentrates in those zones until the material gives way.
Sharp contact points make things worse. Patio furniture corners, firewood stacks, trailer edges, and roofing materials all create friction that slowly weakens the surface.
How to prevent it:
- Choose a tarp with reinforced edges and rust-resistant brass grommets — these distribute stress instead of concentrating it.
- Match thickness to the task: 14 Mil or 16 Mil for regular outdoor use; 20 Mil for heavy loads, sharp edges, or long-term coverage
- Secure the tarp snugly but avoid over-stretching — if all the tension sits in one corner, that corner will eventually fail.
Why Tarps Leak
A waterproof tarp that leaks is almost always a setup problem, not a material defect. The most common culprit: water pooling in the center. When rainwater sits in one spot, its weight stresses the material, seams, and tie-down points over time, eventually creating weak spots that let moisture through.
How to prevent it:
- Create a slight slope so water runs off naturally, rather than collecting
- Size up: The tarp should hang over the sides of whatever it's covering so runoff drips away rather than running back underneath.
- For firewood, garden tools, or patio furniture, a 14 Mil or 16 Mil tarp is typically sufficient; for boats, trailers, or year-round jobsite coverage, step up to 20 Mil
Why Tarps Blow Away
Wind is often harder on a tarp than rain. When air gets underneath, the tarp acts like a sail — and that lifting force puts enormous strain on every grommet and tie-down point.
How to prevent it:
- Don't rely on just the four corner grommets; add tie-down points along the sides to distribute tension
- Keep edges tight and close the gaps where wind can get underneath
- For large tarps or exposed locations, use ratchet straps or heavy-duty bungee cords rather than standard rope — they hold tension better as the tarp flexes in gusts.
How to Choose a Tarp That Actually Lasts
The right tarp depends on the job. Here's a quick reference:
| Use Case | Recommended Thickness |
|---|---|
| Light temporary cover (camping, moving day) | 8 Mil or 10 Mil |
| Regular outdoor use (furniture, firewood, tools) | 14 Mil or 16 Mil |
| Heavy-duty or long-term coverage (boats, trailers, jobsites) | 20 Mil |
Beyond thickness, look for four features in any tarp worth buying:
- UV-resistant material — sun degrades tarps faster than rain; UV protection extends lifespan significantly
- Fully waterproof coating — not just water-resistant; full waterproofing holds up under prolonged rain and pooling
- Reinforced edges and corner patches — the most-stressed parts of any tarp; reinforcement here matters most
- Rust-resistant brass grommets — steel grommets corrode, weaken, and eventually tear through the surrounding material
Size matters just as much as material. A tarp that's too small will stretch, shift, and leave gaps — and a stretched tarp tears sooner.
Frequently Asked Questions
What does "Mil" mean on a tarp? Mil refers to thickness in thousandths of an inch. A 20 Mil tarp is thicker and more durable than an 8 Mil tarp. Thicker tarps are heavier but significantly more resistant to tearing, punctures, and UV degradation.
Can I use the same tarp for firewood and a boat? You can, but it's not ideal. A 14 Mil or 16 Mil tarp works well for firewood. A boat or trailer stored year-round benefits from a 20 mil tarp with UV resistance to withstand extended exposure.
How do I stop my tarp from sagging in the middle? Run a rope or ridge line under the center of the tarp before securing the edges. Even a slight peak prevents water from pooling, which extends the tarp's life and keeps covered items dry.
How long should a quality tarp last? A well-matched, properly secured 14–20 Mil tarp used outdoors can last 3–5 years or more. Thin tarps used beyond their intended load tend to fail within a season.
Patiobay heavy-duty waterproof tarps are available in 8 Mil, 10 Mil, 14 Mil, 16 Mil, and 20 Mil — so you can choose the right thickness for your specific situation, whether you're covering patio furniture for the winter or protecting a work truck on a long jobsite.