Built before modern air-conditioning, Charleston is a city whose definition of indoor/outdoor living is more French doors than floor-to-ceiling glass, a standard that is vigilantly upheld by local preservation groups. So when web developer Rich Yessian and architect Kevan Hoertdoerfer submitted plans to set a steel sanctuary, complete with a roof garden, atop a warehouse that dates from 1858, they prepared for an uphill battle.

“The anticipation going in was that there would be a lot of pushback,” notes Hoertdoefer, wryly. But his client’s wishes were clear.

Inspired by the condos that crown taller cities like New York, Rich dreamt of living somewhere that collapsed the distance between work and nature. When his company, Blue Ion, relocated to the top floor of a warehouse downtown, he saw his chance.

“In our previous office, there was a ladder that took you onto the roof,” he recalls. “I thought that was really cool, to have the ability to pop up and hang out.” Hiring Hoertdoerfer, who oversaw the renovation of Blue Ion’s workspace, Rich set out to determine if the warehouse—and city—could support a rooftop addition that replicated that natural connection.

The proposal Hoertdoerfer came up with, which called for installing a new, double-height story on a large steel foundation, seemed certain to run afoul of traditionalists.

Yet urban renewal can make strange bedfellows. The neighborhood had recovered slowly after Hurricane Hugo hit in 1989, and it was still in flux when Rich arrived more than 20 years later. “There was a sweet spot for this project where the preservation groups felt comfortable supporting it,” says Hoertdoerfer, adding, “If it was two blocks in a different direction, they might have been more reluctant.”

The architect took that blessing and teamed with Charleston Plantworks and general contractors Mark Regalbuto and Andy Meihaus of Renew Urban Charleston to design a perch that provides outdoor interludes during Rich’s downtime, beginning with an elevator that opens onto a patio. From a set of barn doors, tigerwood steps rise toward an alfresco dining area and a deck with a hot tub. When Rich hosts gatherings or unofficial office happy hours here, operable louvers, arranged in a bold, abstract pattern, offer privacy. The network of terraces culminates in a succulent-planted roof with views of downtown and the Arthur Ravenel Jr. Bridge.

It’s possible the home’s runaway success represents a shifting attitude towards modernism in one of the country’s oldest cities; last November, it was honored with a Design Excellence Award by the municipality. But for Rich, it’s a personal triumph, one he’s still marveling over: “I’m just surprised it played out as well as did without it having been done before in Charleston.”