Park Avenue has played a particularly entrancing muse for decades, as writers from Truman Capote to Candace Bushnell would attest. “Once you’ve seen New York and you’ve seen the best, you don’t want to go back,” says designer Frank Babb Randolph, who was recently enlisted by a pair of longtime clients to infuse some of that Upper East Side elegance into their condo in the Washington, D.C.’s Kalorama neighborhood. “This couple spent a lot of time in New York, staying in beautiful apartments or hotels, and wanted something really classical.”

There was just one teensy problem: Their newly chosen abode was just 14 years old, about as classical as a Midtown medical office, without any molding or detail. “It had lovely space and light, but it didn’t have any feeling of connection,” Randolph explains. “So we totally gutted it.”

Working with architect Christian Zapatka, he set about making changes to the home’s interior to create a feeling of stately grandeur.  “We upgraded all the doors and made them two feet taller, so even though the ceilings are only nine feet, they look eleven,” says Randolph. Underfoot, they installed white oak chevron flooring and, in the 20-foot-long cross hall, checkerboard marble that’s been honed to look as if it was worn over time. “The border doesn’t diminish the width of the hallway at all—it defines it,” says the designer. “It’s kind of a trick.  When you put a border on something, you think, ‘Oh, it closes it in,’ but it didn’t do that.”

Another one of Randolph’s other magic tricks for a stunning effect: lacquering the ceiling. “You have to have a new ceiling to do it, because it has to be perfect,” he says. Here, they used about seven coats of Benjamin Moore’s Super White paint in a high gloss sheen, sanding each layer in between. “The final coat has got a gleam to it—it’s like a pond up there,” he says. “It’s almost a floating ceiling, iridescent and pearl-like.”

These peripatetic clients had amassed a stash of accessories from travels around the globe—including Fortuny pillows brought home from their Venetian honeymoon—which the designer arranged with a curatorial eye. Randolph selected antiques that would add to the collected aesthetic but not distract, including a demi-lune table, Danish plaster medallion, and zodiac prints. “They’re 19th century and were actually prints or lithographs, and then somebody later on colored them,” he says. “They’re so beautiful because they’re in these soft, soft shades of green, which picked up the pair of chairs that are in the dining area.”

Visitors may notice one item that is notably absent throughout the home. “There is not a rug in the apartment,” Randolph says. “Putting a rug down defines the space too much, and we didn’t want to interrupt that flow between rooms. The minute you put a rug or a carpet down, all of a sudden the space is eaten up.” The final result feels expansive, like a walk through the Greek and Roman wing of the Metropolitan Museum of Art. Although these clients technically downsized, Randolph says, “they feel more elegant in this space than they did in their big house.”