How to Choose a Waterproof Cover for Outdoor Equipment
Most outdoor covers do not fail because the fabric leaks. They fail because they are the wrong size, they come loose in the first gust, or they seal in damp air and let the gear underneath rust. A good choice starts with the job in front of you, not with a thickness rating. This guide helps you pick the right cover from our range for an air conditioner, a patio table or almost anything else, and shows how to put it on so it works.
Start here: three jobs, three covers
We sell three kinds of waterproof cover for outdoor equipment: poly tarps, AC top covers and round waterproof patio table covers. We do not make covers cut for a particular grill, generator or pool pump. For those, a tarp is the nearest thing we carry, and the sizing and securing advice below was written with that in mind.
Reading the label
Four terms show up on almost every product page. Here is what each one tells you, and what it leaves out.
| Term | What it tells you | What it does not tell you |
|---|---|---|
| Waterproof | Water does not soak through the fabric. | Whether the cover fits, stays on, or lets damp air escape. |
| Mil (tarps) | Thickness. One mil is 0.0254 mm, so 5 mil is about 0.13 mm and 15 mil is about 0.38 mm. | How well it will hold up in your wind. Thicker is stiffer and heavier, which can make it harder to handle. |
| GSM (AC covers) | Fabric weight, in grams per square meter. | Whether it blocks water. Our 150GSM cover is a mesh, and our 350GSM cover is solid. |
| Mesh | Air passes through, leaves and debris do not. | Rain protection. A mesh is not a solid waterproof sheet, so do not expect it to keep gear dry in a storm. |
Our covers, one by one
Each row has a photo and a number. The same numbers appear in the chooser above.
| No. | Photo | What it is and what to check | Where to get it |
|---|---|---|---|
| 1 |  | Poly tarp. Laminated, woven polyethylene. The seams are heat-sealed, and the edges are reinforced with polyethylene rope. Blue is 5 mil, silver and white are 10 mil, brown is 15 mil. Finished sizes run from 5′ x 7′ to 30′ x 40′, but each color has its own set. The listings note that a tarp can measure up to about 3 inches under its stated size. | Tarps: blue 5 mil, silver 10 mil, or all four colors |
| 2 |  | Grommet. The metal-lined hole you tie through. The listings describe rust-resistant aluminum grommets, placed roughly every 3 to 3.5 feet along the edges. | On every tarp |
| 3 |  | Mesh AC top cover. 150GSM mesh vinyl, black, with reinforced edges and corners and four bungee cords. Made to cover only the top of the unit while air passes through. | AC covers, 150GSM (28, 32 or 36 in.) |
| 4 |  | Waterproof AC top cover. 350GSM vinyl, black, also with four bungee cords. A solid top that keeps leaves, snow and rain off, with air still reaching the unit from the sides. | AC covers, 350GSM (28, 32 or 36 in.) |
| 5 |  | Round waterproof patio cover. Waterproof polyester with wire rope sewn into the hem and a tightener to pull it snug. The listing suggests dining tables, lounge sofas and round trampolines. Measure your furniture first, since the size is given for the cover. | Waterproof covers (look for “Waterproof Patio Furniture Cover”), for example the 9 ft cover |
Round table covers are filed with our above-ground pool covers, so that category page shows both. The listings also use a few different color names, including a sky-blue print, so check the photo before you order.
The tarp listings add that the silver color reflects sun, which keeps what is underneath cooler than a conventional tarp would.
Five ways a cover goes wrong
- Water pools in a sag. A flat or slack top holds a puddle. The weight stretches the fabric and presses damp against the item. Fix: give the top a slope, and avoid a cover far bigger than the item.
- It flaps. Loose fabric catches wind, snaps against corners and wears through. Fix: fit it closely and tie it in several places.
- It traps moisture. Waterproof also means damp air stays in. Fix: cover dry things only, leave a gap at the base, and check underneath after a wet spell.
- It rubs. A cover that moves scrapes on sharp corners or rough ground. Fix: pad sharp edges, and keep the skirt off the ground.
- It wicks. An edge that trails on wet concrete or soil draws water up into the fabric. Fix: stop the skirt a hand’s width above the surface.
Getting the size right
Tarps
A tarp is a flat sheet, so it has to be big enough to wrap the item. Measure the length (L), width (W) and height (H) at the widest, deepest and tallest points, handles and shelves included.
If you would rather have the skirt stop short of the ground, which is usually better, you can choose a tarp a size down. Because our tarps are sold as finished sizes, compare your numbers with the size options on the product page.
AC covers
The product page asks you to measure the unit. Its guidance is to choose a size larger than the AC unit’s top, so the four corners overlap the edges. All three sizes (28, 32 and 36 in. square) come with four bungee cords.
Round table covers
Measure the furniture, then pick the cover that clears it all round with the hem hanging below the top. The wire rope hem pulls it snug under the edge.
Keeping it in place
Wind is what moves a cover. These habits matter more than the cover’s thickness:
- Use every anchor you can. Tie each corner first, then the edges between them. One strap across the middle leaves the corners free to lift.
- Do not over-tighten. Snug is enough. A cover that is always under tension tears at the seams.
- Use soft ties on a finish. Bare hooks scratch paint and can snap back. Rope or bungee balls through the grommets are gentler.
- Pick ties that match how often you remove it. Rope can be undone and reused. A zip tie has to be cut off. Our zip ties are sold separately, and we do not sell nylon rope or bungee balls.
We do not publish wind ratings for these covers. In a storm, the safest cover is the one you took off and put away.
AC units: the rules
That is why both of our AC covers cover only the top. Pick the one that matches your weather:
- Falling leaves and debris: the 150GSM mesh cover (3). The product page calls it breathable.
- Snow, ice and rain on a unit that is switched off: the 350GSM waterproof cover (4).
Before you put a cover on, clear leaves from around the base and look for standing water or damage. If you are unsure what your unit needs, follow the maker’s own maintenance guidance.
Everything else outside
Patio furniture. Dry the furniture first. A round table and chairs fit under a round waterproof cover (5). For a rectangular set, a tarp sized as above and tied at the grommets will do. Two separate covers hold better in wind than one big one that can balloon.
Pool equipment. Pumps, hoses and filters are awkward shapes you check often, so a cover you can lift off quickly beats a thicker one. We do not make a cover for pool equipment. A tarp can shelter it if you leave room for air and keep access clear. For the pool itself, see our swimming pool covers.
Garden and lawn gear. A cover is a weather barrier, not a shed. Anything with fuel, a battery or electrical parts is better stored under a roof.
A seasonal checklist
| When | Do this |
|---|---|
| Spring | Lift the covers and look underneath for rust, pests or damp. Check grommets, seams and ties for wear. |
| Summer | Take solid AC covers off. Keep an eye on any tarp that sits in the sun for long periods. |
| Fall | Brush leaves off the covers each week. Clear leaves from the base of the AC unit before you cover it. |
| Winter | Knock off heavy snow when you can do so safely. Remove any solid AC cover before the system runs. |
| Always | Let a cover dry fully before you fold it, and skip harsh cleaners that can damage coatings. |
Questions we get
Are your blue tarps waterproof?
The listings describe our tarps as waterproof and UV resistant. Blue is the thinnest at 5 mil. For rougher use or a longer stay, look at the 10 mil silver and white, or the 15 mil brown.
Why might a tarp come up a little short?
The listings say a tarp can be up to about 3 inches smaller than its stated finished size. Add a little margin when you choose.
Can I use a tarp as an AC cover?
Not as a wrap. A tarp over the whole unit is exactly the fully covered setup to avoid. Use one of our AC top covers.
Does the mesh AC cover keep rain out?
It is built to keep leaves and debris out while air passes through. For rain and snow, choose the waterproof 350GSM cover and remove it before running the unit.
Do the covers come with ties?
AC covers come with four bungee cords. The tarp listings do not mention any ties, so plan to bring your own.
Pick the cover for the job, size it from real measurements, tie it down in more than one place, and let the equipment breathe. Do those four things and the fabric has a much easier time.