Some might call it Mission: Impossible. The client wanted sleeping for six,a home office, and a kitchen in which he could make a Thanksgiving feast, plus seating for 10 dinner guests—all in a 400-square-foot studio apartment.

Said studio, on the 15th floor of a prewar building in Chelsea, one of Manhattan’s booming neighborhoods, had been owned for more than 10 years by Paul and Billie Andersson. The couple had purchased it as a home for their daughter Andrea, when she was a graduate student at Columbia University. After earning her doctorate, Andrea decided to stay in the city, making room for a new husband in the residence. When they had a child, the young family moved to a larger space, leaving the Anderssons with a vacant apartment at an increasingly desirable address. Rather than sell, the couple decided to turn it into a pied-à-terre for their frequent visits to the city. But they knew they would have to make some changes: “It looked like a big hotel room,” says Paul, a defense trial lawyer from New Orleans and a design buff.

Finding a professional was easy. When she was living in the building, Andrea had befriended a neighbor, Robert Garneau, a Canadian-born architect who had converted his family’s apartment into a savvy, space-maximizing home (“Stow Aways,” March 2011). At the time, Garneau, who had previously worked for Nicholas Grimshaw and now teaches at Columbia, was just opening his own office, Architecture Workshop PC , in partnership with Eric Ansel. When he heard of the Anderssons’ renovation wishes, Garneau leapt at the challenge. “We knew the minute he walked in that we were going to work together,” says Paul.

Garneau proved to be an excellent choice—the architect met the family’s demands, and then some. The apartment is now a jewel box of meticulously crafted parts and has been lavished with awards, winning plaudits from local, state, and national chapters of the American Institute of Architects. Staying there “is simply heaven—it’s like going on a vacation,” says Paul, though he notes that the cost of the project rose from about $150,000 to $250,000 during the process.

Garneau explains that the additional expense was primarily due to the installation of a pivoting wall. “They cost as much as a car,” he says. But the unit was added to provide privacy. Many Andersson family members, including two of the couple’s three daughters and their families, use the apartment when they visit the city.

The wall not only pulls out, but contains a generous array of drawers and cabinets in its backside. It’s all constructed of plywood, as is the entire concealed area, providing a striking contrast to the cool white walls in the rest of the apartment. A Murphy bed, stowed in the rear wall, easily opens to provide cozy sleeping for two. There are closets fitted with drawers andpull-down rods on both sides of the bed. When the bed is hidden away, the space can serve as a small study or sitting room. A cutout in the pivoting wall allows a view through to the other half of the room and lets in light from the apartment’s original large and elegantly wrought windows, which were left intact and outfitted with new sills, a radiator cover, and a recess for pull-down shades and lighting.

When the pivoting unit is closed and flush against the wall, the room appears to contain one continuous line of floor-to-ceiling storage, broken only by cutout ledges illuminated withconcealed LED lights that add both openness and warmth. Garneau used ash throughout the apartment to maintain a uniform palette.

In this project, God is indeed in the details. A floor-to-ceiling door between the windows glides open, revealing cabinets that store home office supplies. The multipurpose dining table, custom-designed by Garneau, becomes a desk or a prep counter and can adjust in height from 28 to 40 inches.

The galley kitchen, too, is a model of efficiency. The backsplash even slides open to reveal more storage. While the space is small, Paul, an experienced chef, happily cooks for company. “We’ve actually had twelve people here,” he notes of the apartment’s now-spacious accommodations.

The bathroom also got a complete makeover. Once small and cramped, it now seems roomy thanks to the removal of the bathtub, which the Anderssons happily relinquished in exchange for a curbless shower and a double sink. The door and cabinets are fumed mahogany, which holds up well to moisture, says Garneau. Environmental sensitivity was also high on the agenda: All the wood is sustainably harvested, the finishes are low-VOC, and the fixtures are low-flow to minimize water consumption.

“It’s a new kind of luxury,” says Garneau. “It’s not about space or luxurious materials. It’s about the kind of craftsmanship found on yachts and private airplanes.”

Bedroom

Made entirely of ash plywood, the custom unit with a pivoting wall contains a Murphy bed that unfolds to carve out a private bedroom for two, complete with built-in closets, niche shelving, and Tolomeo task lighting from Artemide.

Living Room

Configuring the bedroom leaves a sizable lounge area on the opposite side of the partition; it’s furnished with a compact sofa bed that can accommodate two overnight guests.

Dining Room

Tucking away the bedroom opens up the apartment’s living area to a space that can accommodate a table with seating for 10.

Kitchen

With adjustable-height legs and leaves that can fold down to create a smaller surface, the lightweight dining table double as a standing workstation. The adjacent wall panel slides to reveal pantry shelving.