After several years in San Francisco, Casper Mork-Ulnes, a Norwegian architect, and his wife, Lexie Damner Mork-Ulnes, an American furniture and interior designer, decamped to Oslo. The draw? A chance for Casper to open a second office of his firm, Mork-Ulnes Architects, and for the couple to raise their children, Lucia, seven, and Dagfinn, five, close to great skiing and to the family farm, a half hour south of the city. “Despite the fact that Casper would need to fly back and forth to the San Francisco office, Oslo sounded like utopia,” Lexie says.

When they got to the farm, Lexie tirelessly scoured the website finn.no for a new home. (In Norway, real estate agents don’t represent buyers.) She soon found a 1,300-square-foot flat in an 1896 neoclassical brick-and-stucco building, in Oslo’s central St. Hanshaugen district, next to a large city park. The apartment had high ceilings and wood floors—but what appealed to the Mork-Ulneses most was its ground-floor location. “There were no steep stairs to climb. You could literally throw groceries in through the window!” Lexie says. “And because it was located just across from the park, it was a great apartment for kids.”

However, their affordable fixer-upper wasn’t quite utopian. For one thing, it was depressingly dim. Although the three lofty living spaces, arranged as an enfilade, had big, glass-paned casement windows, little sunlight pen-etrated them during winter. Two small bedrooms and a tiny kitchen opened onto a dark interior courtyard that saw even less light, and the entry hall was windowless.

The couple pulled off a six-month renovation for under $200,000 with help from a Polish handyman who lives on the family farm as well as building materials from Norwegian big-box stores like Maxbo and ByggMax, Baltic birch plywood shipped from Poland for half of what it would have cost to purchase it locally, and paint from Flügger. Hitting a fine balance between clean-lined, white-walled Nordic minimalism and a California-inspired penchant for textures and organic forms, the design duo took their home from dark to light and from cramped to orderly. Here’s how to replicate the Mork-Ulneses’ best design moves, from controlled color to the perfect pale wood finish.

Make it Yours

Let the Light Flow
Although Lexie was concerned about maintaining privacy in their ground-floor apartment, Casper says, “The most obvious way to bring more light in was to eliminate curtains on the front windows”—and to move all the public rooms, including the kitchen, to the front of the apartment. The architect then cut out sections of the interior walls to form clerestory windows, which bring natural light into the bathrooms, hallway, and bedrooms in the back of the apartment. These windows “allow the ceiling to flow visually from one room to another, thereby making the spaces feel bigger and connected,” Casper says.

Spots of Color
The couple chose white for the walls, but “used saturated colors in limited areas to give our rooms personality,” Lexie says. One big experiment was in the entry hall, which is windowless and has five doors. “I wanted to create an ombré effect in that narrow space to suggest a source of light at the end of the tunnel,” she says. “So, I painted the laundry closet door a dark blue and the entry door and wall at the other end of the hall a light, sky-blue color.”

Warm Woods
During their early months on the family farm, near Oslo, the couple embarked on a few DIY projects, including building a 12-foot-long Norwegian spruce bench that doubles as a catchall for shoes in the front hallway. “In Norway, you come in with your feet covered with snow, and shoes have to come off right away,” Casper says. The wood plank was milled from a tree on the farm. “Furu [a soft pine] is not an ideal wood for furniture, but it really works in this space since it matches the floors,” says Lexie, who once worked as a furniture designer at Pottery Barn Kids.

Brighten Up
To lighten their floors and cabinets, the couple first sanded the wood; then coated it with Flügger lut, or lye, which removes any pinkish hue; and then applied white oil, which removes yellow tones. “Lut is commonly used to cure dried Norwegian cod, but when you use it with white oil, it results in a brighter, bleached white color,” says Casper. They finished the wood with a coating of hard wax and white oil that seeps in and hardens to form a protective layer.