A pair of modernists learn to love the ornate details of their South End Brownstone.

Decades before Ikea became an international phenomenon, a young Katarina Edlund took Scandinavian design for granted. She grew up in Malmö, Sweden, among Marimekko wall hangings and crisp Scandinavian furniture. Her husband, Massachusetts native Scott Slarsky, discovered modernism at a slightly later age, while studying architecture at Columbia and later working for Spanish architect Rafael Moneo in Madrid. Now he creates angular, elegant projects at Boston-based designLAB architects, while Edlund, an architect and general contractor, is a principal of the design-build firm, Edlund + Haas.

Given their modernist pedigree, it is surprising the couple lives in a historic South End bowfront brownstone, with its curved walls and lavish plaster medallions and cornices. Built in 1858 as a 6,000-square-foot home on Chester Square, it faces what was once a verdant park with elaborate fountains (now a heavily trafficked strip of Massachusetts Avenue). The brownstone had served as a boarding house since 1872, and, more recently, a childcare facility. Edlund and Slarsky bought the severely damaged structure in 2005 with every intention of gutting it.

But during demolition, they began to discover its countless treasures and stories. In a closet, the couple discovered extraordinary cast-iron fireplace covers molded to look like flames. On one wall, they found remnants of a mural featuring a large enigmatic eye, leading them to speculate that this house was once a pan-African church. Suddenly, the modernists found themselves falling in love with history and meticulous detailing.

Changing course, they assembled a small army of contractors—roofers, masons, plasterers, and wood refinishers—many specializing in historic preservation. "They sang while they worked," says Slarsky. "And I swear to God the vibrations of their singing went into the mortar," he adds.

In many cases, Slarsky and Edlund allowed their expert artisans to make many of the design decisions. They let Daniel DiPaolo and Jef Grinarml of Preservation Carpentry, for example, decide where to place the newel post when reassembling a period staircase given to them by their next door neighbor. "We had ideas," Slarsky explains. "But we had so much faith in the aesthetics of our craftspeople...we weren't architects who dictated; we were having a dialog with them."

But this is not your average Boston brownstone renovation. In a city where a slavish allegiance to historicism can thwart creativity, Slarsky and Edlund forged an unlikely union of modernism and Victoriana—imagine Le Corbusier teaming up with Henry Hobson Richardson. As Slarsky, 43, explains, "If we had been too wary of historicism, I think we could have seriously damaged this house." Edlund, 41, who was the general contractor for the project, adds, "We had seen renovations where people did not preserve these details and it feels very sad. It feels like a series of missed opportunities."

They abandoned the typically dark Victorian palette in favor of white, silver, and gray to unify disparate styles and tempers in what could have quickly become decorative overload. In the kitchen, for example, a modern Poul Henningsen artichoke lamp looks great hanging from a Victorian medallion, united by the color white. When it comes to the stunning Florence Broadhurst wallpaper that hangs in the front foyer and upstairs bath, restrained monochromatic hues are paired with exuberant patterns.

Throughout the design process, they broke many rules. For starters, they decided to move the kitchen to the parlor level. "If we kept it downstairs where it originally was," says Slarsky, "we might have never come upstairs." Inverting the standard kitchen layout, they placed the sink and oven in the middle of the room, creating two marble-topped islands.

On the garden level, where the couple and their children, Olivia, 7, and Odin, 3, spend lots of time, there are two bedrooms, two baths, a family room, and a long rectangular room with one giant family closet, created with Ikea shelving and sliding doors—"Katarina's brilliant design idea," says Slarsky. Although there are occasional morning traffic jams as the family scrambles to get dressed, it's a system that frees the bedrooms from dressers and clutter.

Standing in their bedroom, which is decorated with several of Edlund's heirlooms, like a Marimekko wall hanging and an early Hans Wegner chair, Slarsky admires the sensuous curves of the walls. "They're so ubiquitous in the South End," he says, referring to the area's rows of undulating Victorian facades. "It's almost like a sheet of fabric that's waving, as you go up and down these streets." He then turns to Edlund and asks, "I would never make a curved building. Would you?"

Apparently it's a rhetorical question as his wife smiles and changes the subject; neither Slarsky nor Edlund seem likely to design a curved space any time soon. Yet it's clear the couple is thrilled to inhabit one.