The sleepy fishing village of Fjällbacka, on Sweden’s rugged west coast, is peppered with houses built in the local vernacular—with painted clapboard and steeply pitched roofs. One glaring exception is the bold, contemporary summer house belonging to Swede Isaac Pineus and his Scottish partner, Andrew Duncanson, designed by renowned Gothenburg architect Gert Wingårdh.

The couple spend most of the year in Stockholm, where they own a midcentury furniture gallery called Modernity, which Duncanson founded in 1998. They live in the city center in a Victorian terrace-house apartment along with their three-year-old twin sons, Tom and Marc. But they always wanted a place in the country, where they could escape their busy cosmopolitan lives. “It’s every Swede’s dream to own a summer house,” explains Duncanson. “It doesn’t have to be big or elaborate, just somewhere close to nature.”

In 2005, they decided to turn their fantasy into reality. They already had the perfect location in mind—a plot on an acre of land in Fjällbacka, that Pineus’s grandparents bought in 1945 and where the family spent many happy holidays. On the property was a rocky patch of hillside that had grown wild over several decades. Though boulders obstructed the view of the sea, Pineus and Duncanson decided it was the ideal spot for their dream house.

With the location sorted, two key decisions remained: the style of the house and the architect who should design it. In the end, neither decision was particularly difficult. “We quickly realized we wanted to build something that is an expression of its time, rather than a pastiche of a previous era,” recalls Pineus. As for the design, the couple had long admired the work of Gert Wingårdh, the architect responsible for Sweden’s embassy building in Washington, DC, and several characterful residences around Sweden. “Gert is great at making simple houses work well,” says Duncanson. “But there is also usually a twist, which in this case is the hanging boxes and terraces that give the house a sculptural quality.”

Pineus and Duncanson sent the architect a brief to create a building that blurred the boundaries between inside and out, where they could entertain large groups of friends, no matter the temperamental mood of the Swedish weather. Wingårdh’s innovative solution was to attach a series of chunky pine boxes to the building’s facade that provide sheltered terraces off the main living space and the two guest bedrooms. A roof deck on top of the living area provides additional outdoor space, with views over the rocky outcrop to the village and the sea beyond.

Construction began in September 2008 and was completed, on schedule, the following June by a team of trusted local builders, who had previously worked on a house for Pineus’s parents. Duncanson spent over two years sourcing furniture and was delighted to find, on move-in day, that his choices fit perfectly. In keeping with the house’s restrained yet quirky exterior, the interior has a predominantly relaxed Scandinavian feel, with a few surprising details. “I think it would be too expected for us to just fill our house with Scandinavian design,” says Duncanson, who added pieces like the 1980s bar stools by Javier Mariscal and Gerald Summers’s curvy armchair to create a more worldly mix of styles.

For Pineus and Duncanson, the dining area is the biggest success of the interior scheme and their favorite place to spend time. The monumental La Basilica table, by Mario Bellini, is balanced by the lightness of Gio Ponti’s delicate Superleggera chairs. And a traditional Swedish rag rug and an abstract textile wall hanging by Danish artist Bodil Bødtker-Næss provide texture that softens the acoustics in the large space.

Throughout the house, the couple used materials that will stand up to constant use, such as the pine floorboards, which were installed by a local joiner to taper slightly toward one end as they follow the shape of the tree from which they were cut. “We wanted a country house feel, so we like that the floor is developing a lovely warm patina,” says Pineus. “Nothing here is a museum piece; everything is there to be used.”

Having enjoyed the house for a few years now, Pineus and Duncanson are delighted with the way it responds to their needs. “The kids love being able to play outside, and we love the different pace of life here,” says Pineus. “The design also allows us to use the space in so many ways—we’ve had 40 people for lunch before, and there’s space for everyone to sit, both indoors and outdoors.”

The family spends four or five weeks of the summer in Fjällbacka and as many vacations and long weekends as they can manage, despite the five-hour drive. It’s never enough, adds Pineus. “We try to spend as much time here as possible, but of course we wish we could come more often.”