Back in the '80s, the sole purpose of outdoor fabrics was to be utilitarian. As for looks, their green and cream stripes seemed more like a government-issue uniform than a designer statement.

But when the outdoor-fabric brand Sunbrella started creating better designs, its manufacturer noticed something: Employees, the kind with kids and dogs, started using the fabrics in their living rooms.

That was 15 years ago. Once the company made prioritizing design a goal, in the same way it had with technology, sales exploded. And now Sunbrella is joined by a host of other products — called "performance" fabrics for their ease of cleaning and resistance to light and water — that sit side-by-side with design houses' swank fabrics. Sunbrella alone designs collections for high-end companies Donghia, Kravet, Duralee, and Robert Allen.

The outdoors are in.

"These fabrics have come so far in terms of technology, resisting stains, mildew, spills, and fading," said Hal Hunnicutt, vice president of marketing at North Carolina-based Glen Raven, the maker of Sunbrella. He tested the Sunbrella velvet fabric on his own sofa by dumping his cup of coffee (there are chenille indoor/outdoor fabrics, too). It passed that test, and survived Sharpie marks from his kid as well.

In indoor patios, the fabrics won't fade. They're also great for places prone to stains — kitchens, bathrooms, mudrooms — said Jessica Smarsch, senior design manager for Robert Allen Contract, which debuted its first outdoor fabric collection almost a decade ago and has since evolved to incorporate all kinds of design trends: traditional Jacobean florals and matelasse frames, global ikats, block prints and animal skins, or multicolored, whimsical prints.

But this trend isn't solely a result of people wanting more durable fabrics for the indoors, although it's about time homeowners don't have a nervous breakdown when a dinner guest spills their drink on a dining room chair.

As these newer, more chic lines were being introduced, customers began demanding better outdoor living spaces, expanding their expectations for a luxurious home. Fabric manufacturers had extra incentive to elevate their designs to match the nicer furniture while maintaining the products' sun-, mold- and high-water-temperature resistance.

And so the indoors, so to speak, has moved out.

"Outdoor fabric has improved in the last five years in leaps and bounds," said Chestnut Hill designer Mona Ross Berman, who uses performance fabrics for her clients with children because of its inherent durability and water resistance. "I've put it on banquettes in breakfast rooms, on throw pillows on a sofa in a beach house, and even on a bolster pillow in a master bedroom."

Her go-to manufacturers are DeLany & Long for their neutrals and sophisticated palettes, China Seas, and Christopher Farr.

"Sales are increasing as more and more designers and end-users request this type of performance," said Susan Sullivan, vice president of sales for New York City-based design house Pollack.

That's the case with Bella-Dura, a brand of fabrics by New Jersey-based Wearbest that are made from recycled materials and are durable, UV- and stain-resistant, and antimicrobial. The fabric was born after Wearbest president and CEO Irwin Gasner was researching the changing market at the turn of the century and discovered that homeowners were spending more time in their houses. After three years of testing in a lab, Bella-Dura was introduced in 2004.

"People are staying home more and entertaining more and instead of spending lots of money on vacations, we continue to hear about the staycation," Gasner said. High-end design houses like Schumacher and Cowtan & Tout have partnered with Bella-Dura on collections. "In a doldrum market with people spending less and less, we have had 50 percent growth year after year."

Floss Barber, founder of the same-named interior design firm on Locust Street, recommends performance fabrics for both hospitality clients — she plans to use a canvas/linen Sunbrella fabric for a Main Line inn — and for her own living room, where slipcovers resembling cotton duck can withstand grandchildren and summer use.

But there's more to some performance fabrics than cleanability and light- and water-resistance.

Not only can Crypton's patented technology make fabric resistant to moisture, bacteria, and odors — it can be disinfected. Used mostly in hospitals, airports, and restaurants when it was introduced in 1993, CryptonHome Fabrics was introduced for residential use two years ago and sold to furniture manufacturers Century, Henredon, Thomasville, and Flexsteel.

The technology is also included in the collections of high-end design houses Fabricut, Robert Allen, Duralee, and Kravet, available through designers or at Joann Fabric stores.

"You'd think these fabrics are too beautiful to be used outdoors but you can," Gasner said. "Now you can't tell the difference between indoor and outdoor fabric."