Sunbrella Outdoor Fabric Isn't Waterproof. Here's Why That's a Good Thing.

Sunbrella outdoor fabric isn't waterproof. Here's why that's a good thing.

Sunbrella outdoor fabric isn't waterproof. Never has been, and I doubt it ever will be. I lead with that because it's the first question most buyers ask, especially when they're comparing coated polyester or nylon alternatives.

For context, I'm the quality compliance manager at Glen Raven, the company behind Sunbrella. My day job is checking fabric before it ships. Four years, hundreds of rolls a month, more water-spray tests than I can count. I've rejected deliveries that didn't meet spec and signed off on ones that did.

Here's my opinion from that seat: 'waterproof' is the most oversold claim in outdoor upholstery. Not because waterproof materials are useless—they absolutely have a place. But most furniture cushions don't need to be waterproof. They need to shed water, dry out quickly, and avoid trapping moisture. Coatings can work against that last part.

The illusion of a waterproof coating

People assume a coated waterproof fabric is tougher than a woven one. From the outside, it can look that way: water hits, beads up, and rolls straight off. What you don't see is what the coating is doing underneath the surface.

Most waterproof fabrics are a textile base with a PVC, polyurethane, or similar barrier laminated on top. That barrier does the water blocking. It also bears the brunt of folding, flexing, sitting, cleaning, and UV exposure. Over time, coatings micro-crack. They lose flexibility. They start to delaminate around folds and seams. And the failure usually isn't visible until water gets in and the cushion starts to smell.

Look, I'm not saying coated fabric is bad. If you're building rain covers, boat enclosures, or any product that genuinely sits in storm conditions, coated nylon or polyester is the right family of materials—and yes, you should read every page of the nylon fabric catalog your supplier offers. But an outdoor cushion is not a rain cover. It's closer to a pillow that needs to breathe.

Breathability: the line most spec guides ignore

Here's what frustrates me as someone who reads product specs all day: you can work through an entire breathable fabric specification guide and rarely see breathability discussed as a number. They list water repellency (AATCC 22), hydrostatic head (AATCC 127), abrasion cycles (Wyzenbeek or Martindale), and UV stability. But the property that decides whether a cushion dries overnight rarely gets a mention.

Air permeability is measured with a straightforward test (ASTM D737). It tells you how much air can pass through a given area of fabric in a minute. If that number is near zero, you're buying a barrier. For outdoor furniture, a barrier is usually the wrong answer.

Why? Because a cushion sits on foam. It picks up body heat, humidity, morning dew, and the occasional thunderstorm. If the fabric seals one side completely, moisture gets trapped inside. Then you get condensation, mildew, and odors. That's not a fabric failure. It's a physics failure, and no waterproof label fixes it.

Sunbrella furniture fabric is breathable because it's woven from solution-dyed acrylic fibers rather than coated. The water resistance comes from a durable finish and a tight weave, but air can still move through the structure, and that helps moisture escape. Solution dyeing also means the color is part of the fiber, not a surface layer that can peel or wear off. Not a typical selling point, I know. But it shows up in the field faster than any brochure.

If you're comparing options and can't find an air permeability number, ask the mill for one. If they look confused, that tells you something.

The 18,000-yard order that changed how I talk about specs

The order that really changed how I talk about this arrived in the spring of 2024. A distributor serving resort properties sent us a request: 18,000 yards of Sunbrella outdoor fabric, with a note in bold letters: 'fabric must be waterproof.' They'd been dealing with complaints about cushions that stayed damp after storms. Their conclusion was that they needed to lock water out completely.

There is no waterproof Sunbrella. We said so. We also asked a question that slowed the process down: what exactly are you trying to solve? Damp foam. Odor. Guests who don't want to sit on wet cushions hours after a storm.

So we set up a side-by-side test with their team. Coated waterproof material versus standard Sunbrella outdoor fabric, both built into identical cushions, both soaked, both left to dry. The coated sample kept water off the face of the fabric. But moisture still found its way in through the seams, and once inside, it couldn't escape. The Sunbrella cushion dried much faster. After a week, the difference in the foam cores was obvious. (I should probably turn that test into a proper write-up; it was way more dramatic than I expected.)

They didn't need waterproofing. They needed drying time. Airflow. A cushion construction that doesn't trap water. Once they knew that, they changed the inner liner, added drainage, and specified Sunbrella. Their first season after that change had a fraction of the damp-cushion complaints from the previous year.

So when would I tell you not to spec Sunbrella?

I want to be honest about the limitations because they're real. There are cases where a woven water-resistant fabric is the wrong call:

• You actually need a waterproof membrane. If the product is a tarp, an inflatable, a marine item, or anything with a real hydrostatic head requirement, stop looking at upholstery fabrics. Spec a coated nylon or polyester from a waterproof fabric OEM. Ask for hydrostatic head test data before you commit.
• You face harsh chemicals or extreme industrial abrasion. Concentrated acids, solvents, and heavy scraping will overpower any flexible fabric. PVC-coated or rubberized textiles are the more appropriate engineering solution there.
• Your product is designed to last two seasons at the lowest possible price. If that's the business model, a polyester or olefin fabric may meet your need. That's a legitimate decision. It's just a different product promise.

Bottom line: buy the spec, not the claim

After four years of watching outdoor fabrics fail in the field—and inspecting the ones that don't—I keep coming back to the same conclusion: breathable water resistance beats a waterproof label for most furniture and upholstery applications.

What I mean by that is simple. A spec is a promise about real-world behavior. Will this material shed rain? Will it dry before mildew has time to form? Will the color hold after two summers by the pool? Will it stay flexible instead of cracking? Those questions matter more than a dramatic '100% waterproof' claim on a datasheet.

Sunbrella doesn't promise to be something it isn't. We promise water resistance, breathability, and fade resistance. Our warranty backs that up—current terms are on sunbrella.com if you want to check. No fabric is indestructible, and no fabric should be sold as if it were.

So next time someone puts 'waterproof' in front of 'Sunbrella outdoor fabric' on a spec sheet, pause. If the application truly calls for a sealed membrane, you're shopping for the wrong material. And if you need a cushion that survives real summers, you're probably looking at the right one.