The Integral House

A man’s home may be his castle, but in James Stewart’s case, it was also his showcase, workspace, pleasure palace, and personal concert hall. The Toronto-born mathematician, author, violinist, gay activist, and philanthropist built what many consider the most extraordinary private residence ever seen in Canada, in one of Toronto’s most exclusive neighbourhoods, Rosedale. Wandering through the remarkable structure, one is struck by the almost obsessive attention to detail, the high quality of the materials, and an architecture that takes delight in its own complexity. Completed in 2009, Integral House, a beautiful singularity, is truly unique. And now it is for sale (listed by the Trilogy Team for Sotheby’s International Realty): asking price, $28-million.

Stewart, who died last December of bone-marrow cancer, left instructions that the money raised from the sale of his house be used for cultural purposes.

If this James Stewart doesn’t sound familiar, that’s because you’re not a university student taking calculus. Chances are that if you were, you’d know exactly who he is: the biggest-selling calculus textbook author in the world. His books have been used around the planet since the 1980s. Millions of copies have been sold, in more than a dozen languages. In addition to helping countless students learn the mathematics of change, Stewart’s books made him a rich man.

Once inside it reveals three more floors that plunge down the side of a steep ravine. Photo by Edward Burtynsky.

In the late 1990s, he conceived the idea of building a residence that would combine both his love of architecture and his most passionate love, music. From childhood, Stewart was torn between the violin and math. In the end, he decided it would be better to be a mathematician whose hobby was music, rather than the other way around. But he played on regardless; for many years, he was the principal violinist with the Hamilton Philharmonic. After moving into Integral House, Stewart also became something of an impresario, organizing spectacular concerts that included a world premiere of a piece by Steve Reich, as well as recitals by the likes of Canadian soprano Measha Brueggergosman.

Indeed, it was she who sang Richard Strauss’s sublime Four Last Songs at Stewart’s wake in November 2014—a wake held at his own request, which took place just weeks before his death. As he said himself that memorable evening, once he saw who was performing, he realized it was an event he couldn’t miss.

Building Integral House kept the architects busy for six years: two for planning and approval, and four for construction.

“There were two basic requirements for the house,” Stewart explained. “I wanted the performance space and I wanted curves. I wanted a house for entertaining.”

Stewart’s architects, Brigitte Shim and Howard Sutcliffe of Toronto, presided over the project for the better part of a decade. Their firm, Shim-Sutcliffe Architects, has won no fewer than 13 Governor-General’s Awards since being formed in 1994. But this project was unlike any other.

“Jim was always very soft-spoken,” Shim says. “He was just a really lovely guy, the nicest person you ever want to meet.”

Building Integral House kept the architects busy for six years: two for planning and approval, and four for construction. The curves Stewart wanted became a series of undulating glass walls suspended on vertical oak fins. From the street, the house is only two storeys tall. Even set back from the sidewalk, it stands out from its neighbours in its uncompromising modernity. The building doesn’t reveal its full glory until one gets inside and realizes there are three more floors that plunge down the side of a steep ravine. In summer, many of the rooms look onto a substantial tree canopy. Like some elaborate tree house, it feels intimately connected to the natural landscape of the ravine.

Inside, it is all smooth finishes and unobtrusive high-tech systems. (The control room looks like something from an office tower more than from a private home.) The floors are heated—the living room and entry area floors are honed French limestone—and one of the main stairwells is finished in hand-blown blue glass, with each panel attached to the wall with shaped bronze elements and stainless steel cables. Occupying roughly 18,000 square feet, this is a residence with plenty of space. And although its rooms are laid out for maximum connectivity and comfort, there’s no shortage of out-of-the-way enclaves to sit and chat quietly.

Still, the centre of the house—its architectural, spiritual, and social heart—is the performance area. Located below street level but high above the ravine below, the space is defined by an especially large curve that extends out from the house. The room is large enough to accommodate performers as well as an audience of 150, maybe more on special occasions such as Stewart’s last salon. It’s no Roy Thomson Hall, but Stewart’s wonderfully intimate music hall can easily handle a chamber orchestra playing around a grand piano.

At the centre of the house—its architectural, spiritual, and social heart—is the performance area. Integral House is a home for entertaining.

Though the architectural language is contemporary, the house has a 19th-century sensibility about it, one based on live music performed in elegant surroundings for the enjoyment of a small group. It is frankly elitist, not because it’s socially exclusive but because it aspires to musical, architectural, and cultural excellence. Stewart’s house is less about luxury than the need to be civilized, in an old-fashioned sort of way, through making and sharing music.

On the night of its builder’s farewell salon, the house was in its glory. Its spaces filled with people and music, it came alive in ways that would be impossible on a quiet weekday morning. As visitors wandered through the building oohing and aahing at every turn—the infinity pool on the lowest level was a big draw—they could see for themselves the care lavished on every aspect of the place. The banisters, for example, are wrapped in leather; the glass wall facing the pool can be raised or lowered at the flick of a switch.

Though the house rests on solid concrete foundations, the ever-changing arrangement of fins along the exterior walls, though stationary, adds a sense of movement to the interior spaces. Stand in one spot, you enjoy an uninterrupted view of the ravine below; turn your head to one side or the other, the view is blocked by fins. The glass panes, each one seemingly a different size, range in width from a metre or more to just centimetres. The sheer size of the house and its openness also provided the architects with an opportunity for a series of indoor “balconies” overlooking the concert hall. The most public part of the house, the ground floor, is the location of the kitchen, dining room, and entrance. Here the effect is one of restrained, even austere, elegance. The pleasures of the house await just beyond.

View of The Aldeburgh Connection at the Integral House, performance with soprano Nathalie Paulin. Photo by Bob Gundu.

Up above, the master bedroom suite looks north and east over the ravine and forest below. The bathroom could double as a spa, and though Stewart was a man apparently most comfortable in slacks and T-shirt, his closet is the size of a small clothing store. Mostly though, it’s the view that impresses. The age-old hunger for transparency has been acknowledged here and given full rein. This room is the most well-appointed piece of the sky one can imagine. The same fin-and-curve technique is used, but here the wooden structures are farther apart, minimizing the difference between indoors and out.

This exquisite blurring of traditional distinctions—exterior and interior, natural and manufactured, polished and raw—makes Integral House appealing for more than its stunning architecture. The spaces in and around it have the uncanny ability to put us at ease. Once the initial amazement has worn off and our jaws are back in their sockets, we feel unexpectedly comfortable. Despite the sheer unlikeliness of it all and the improbability of a man like Stewart, brilliant and unabashed in his search for excellence, Integral House is also just that in the end—a house—a place to live, work, and share with others. Configured to accommodate the contradictory needs of the owner’s public and private personae, it isn’t simply an “integral house”, but also a complete house, clever and complex enough to reflect the full range of human experience and—let’s not forget—desire.