Craving more space to raise their young sons, Charlotte and Nick Ivancic traded a tight DC townhouse for a center-hall Colonial in the city’s Wesley Heights neighborhood ten years ago. The ’20s-era abode, set high on a leafy lot with a picturesque stream running below, came fully renovated, another big plus back then. Recently, though, the couple—she’s a healthcare lobbyist and he’s a renewable-energy lawyer—decided to upgrade function and style on the main floor. Having an interior designer in the family provided a leg up.

Nick’s sister, Rachael Rosenblum, who operates a Brooklyn-based design and furniture-restoration studio, understood the mission for an active household with three boisterous boys, now ages 16, 14 and 11, and a dog. The goal: Camouflage the chaos. “They wanted the interiors to reflect the energy they bring into the house,” she recounts. “You can just imagine the boys storming through. They wanted to emulate that with color and pattern but also transform the home to feel more sophisticated.”

The couple first tackled a short list of physical improvements on the 4,400-square-foot home. Having worked with architect Patrick Welsh on an earlier exterior revamp, they re-engaged him to design a screened porch off the living room.

They also tapped the team at Fajen & Brown to help select some finishes and execute several interior-architecture enhancements. Widening the arched room openings and encasing them in white oak added airiness and interest to the first-floor plan. The living room gained bespoke built-ins crafted to conceal the television.

The designer and the owners then began refining their exuberant, yet elevated vision. “They were looking for eclectic interior design,” Rosenblum reveals, “to have modern elegance sprinkled with unexpected notes.” It was a given from the get-go that vintage furnishings, reupholstered in expressive textiles, would figure prominently in the schemes.

“Rachael’s business focuses on exactly what we like—breathing new life into old pieces,” Nick shares.

In the long living room to the foyer’s right, four vintage swivel chairs form one seating area. They sport a vibrant, painterly print from Pierre Frey that spoke to Charlotte and ultimately inspired the space’s bold look. “I would live in a crayon box if I could,” the wife quips. Beyond that grouping, a new, bouclé-covered sofa faces two circa-1970 slipper chairs, recovered in a jacquard velvet based on Tibetan carpet motifs.

As Rosenblum says, “The clients’ passion for vintage finds helped create a layered, livable space that feels timeless and expresses their personal tastes.”

The dining room’s mid-century table and chairs tell a particularly meaningful story. Recently released from storage and refinished, the set once belonged to Nick’s great-grandparents. To turn the handed-down collection into a “super heirloom,” Rosenblum commissioned needlepoint seat cushions with an offbeat twist. The ombre, geometric design incorporates an eye—meant as a phonetic monogram for the initial letter “I” of the owners’ last name. The iris color on each cushion corresponds to a specific family member’s eye; the sixth chair bears a brown eye for Sunny, their golden retriever.

“My great-grandparents had Passover Seders on this set in the ’60s,” recounts Nick. “Now our kids do their homework and eat here. It’s very cool.”

Other spaces received practical and pretty enhancements, too. The foyer’s new curved, built-in bench combines mudroom-type storage drawers with a top cushion dressed in a chic French jacquard. In the kitchen, Rosenblum improved the existing breakfast-area banquette, removing its unforgiving beadboard back and installing cushions done in a lively print. “We wanted a space where you could hang out and have a glass of wine while someone is cooking,” says Charlotte.

The reimagined first floor now offers the livable luxury the couple was after. “We enjoy the space more now,” reports the wife.

“And that’s the main function of your house, right?” adds Nick. “You've got to enjoy it.”