Grand Simplicity - NYTimes.com Classic English coziness meets minimalist rigor for a style that is both timeless and of the moment in the interior designer Rose Uniacke's London home. Seeing how the interior designer Rose Uniacke lives and works, it seems she's more a cross between an architect and an antiques dealer than a decorator. "I like playing with space," Uniacke explains. I don't like furnishing just for the sake of it. I like referencing the context of a building. This is something she has done to great effect with her London home: a grand 19th-century house she shares with her husband, David Heyman, the producer of the Harry Potter films, and their five children. Uniacke started her career as a restorer and gilder. "That was really the birth of my interest in furniture," she says. Her passion for antiques grew after she moved to France in 1994. It was there that she began buying pieces and sending them back to England to her mother, the well-known antiques dealer Hilary Batstone. Upon her return home three years later, Uniacke started working in earnest with her mother. After a customer came in and asked Uniacke to decorate his home, her design business took off. Today both mother and daughter have shops just a few doors down from each other in Pimlico. Uniacke's style is minimalist - monastic at times. Her signature look is quite raw, which she mixes with luxurious touches, like beautiful architectural detailing, high-quality antiques and sumptuous textiles. This elegant combination has earned her impressive design projects like the Marquess of Bute's estate on a Scottish isle and the conversion of a Georgian town house in Marylebone into the head offices for Jo Malone. But it is her own lavish house, a 14,000-square-foot Victorian manse, that has been her most exciting undertaking to date. There are very few houses in London as stately as this one. It was built in 1861, in the Georgian Revival style by the society portraitist James Rannie Swinton as his studio and home. Even then, it was impressive with its ballroom, dramatic domed ceiling and huge glass-roofed conservatory. However, by the time Uniacke and Heyman bought the property in 2007, it was in bad disrepair, having most recently served as the headquarters for a charitable arts trust. As James Graham Stewart, a friend and fellow antiques dealer, recalls, "They were pigs of rooms, great echoing big spaces, without great proportions. To make them friendly was quite a feat, because you walk in now and think, What lovely rooms. But they weren't like that to begin with. The building needed to be entirely restored, but Uniacke was undaunted. "I loved the airiness," she recalls of her first viewing of the place. I loved the generosity and the originality of it. On the day I visited, Uniacke was arranging flowers on a metal table in the conservatory. Just around the corner revealed the designer's first bold gesture: a 12-ton stone cantilevered staircase she had built and installed as it would have originally been in the house. Uniacke, who has a natural talent for turning vast spaces into comfortable rooms, kept the palette fairly neutral throughout the house, with pale walls and unfinished wood floors. The rooms are quite spare but what the designer places in each of them is of the finest quality. The furniture is a combination of her own designs, exceptional antiques (ancient Chinese, northern European, older English pieces) and yards and yards of fabrics (cashmere, heavy linens and lots of Fortuny). On the second floor, the couple's study occupies the space that was once the ballroom, a room of such splendor that it is hard to believe you are in London and not at Chatsworth. Uniacke has furnished it with statement-making pieces like a 17th-century Mughal rug and an octagonal Regency partners desk. At the other end of the room is a large fireplace with a pair of Uniacke's signature deep, plush sofas. The rooms are purposefully uncluttered. "If the space is properly balanced, then the rooms can be simply furnished and allowed to breathe," she says. I like to know where I am, and in that context you can be very minimal. While Uniacke has designed some other lavish features in the house - an indoor pool tucked away in the basement, a large wine cellar, iPad panels in every room to control the sound and video - for the most part, she has let the building, the rooms, speak for themselves. "It's a classical building," Uniacke says. And I want to be true to what I am working with. Even when she is dealing with the more high-tech flourishes, Uniacke applies a discreet touch. In the original studio, where Swinton painted his portraits, she has covered the walls in artists' canvas as a nod to him. What first appears to be a sitting room is actually a screening room. A closer examination reveals several speakers positioned around the room as well as a projector lens peeking out from a hole in the wall. The chandeliers move up and down by remote control to clear the space for viewing. Despite her subtle design work, this is the mother of all screening rooms. And one is quietly reminded that this indeed is the house that Harry Potter built.