For a tiny mews house hemmed in on all sides by neighbouring buildings, Mark Gabbertas's London home feels remarkably light and spacious. That's because — when the weather permits — the doors and windows are flung open and the outdoors is welcomed in, almost doubling the entertaining space and bringing sunlight, wisteria-scented air and walls of foliage into this one-time stable. "The horses and carriage were kept down here," says Gabbertas, pointing to the comfortable sitting room, dining and kitchen areas. "The grooms lived upstairs," he adds, in what's now a bedroom, bathroom and boxroom.

When Gabbertas bought his home 12 years ago, the horses were long gone and the place had been made over in a Seventies style. "It was like a wood-clad sauna with brown shag-pile carpet," Gabbertas remembers. "And when I started to pull down the pine cladding I realised that it was holding up most of the ceiling." Serious work was undertaken; the place was gutted and two space-saving spiral staircases were installed: one in the middle of the ground floor, the other from the small terrace outside the kitchen. The ground-floor rooms were knocked together to form a single space, and the various decks and garden areas were linked to the interior by both french windows and folding doors.

Although Gabbertas could have added valuable square feet to his home by glazing over the side return on the ground floor and the deck on the upper level, he chose to keep them as outdoor "rooms", making "walls" of trellises and greenery, which provide privacy as well as a leafy outlook. Having the garden spaces on different levels and a small, cobbled courtyard at the front allows him to follow the sun, utilising each area at different times of the day and year. The two spiral staircases provide access between one level and another, as well as indoors and out.

But Gabbertas's home wasn't the only thing to witness change: his career also underwent a transformation. Armed with a degree in political philosophy from Durham University, Gabbertas arrived in London looking for a job. His first position was as a motorbike messenger, and his second was at advertising firm Saatchi & Saatchi, where he worked for several years. "It was full-on ­ there was no time for vagrant thoughts," he says. "When I left, it was as though I had taken a blanket off my head and I could see what I wanted to do. And that was be a furniture designer." Gabbertas started to train as a cabinet-maker. "One week it was lavish lunches and fast cars, the next it was travelling by bus and sweeping the floor for £1 an hour."

Having served his apprenticeship, Gabbertas set up his own workshop in Hackney where he worked for eight years, completing a number of high-profile commissions before moving to a design studio within walking distance of his home. The fruits of his labours can be seen all over this compact house, tucked in between the antiques, the artworks and the book-laden shelves.

Wrapped around the corner of the sitting room is a sofa Gabbertas designed for Purves & Purves, and on the other side of the coffee table is a pair of yellow upholstered Tommo chairs, part of a commercial project to manufacture seating for restaurants and hotels. In front of the antique Biedermeier sofa in the dining area is a long Douglas fir table with bench seats that were originally made by Gabbertas for a stand at a design show. "The dynamics of sitting on benches to dine is interesting," he says. "I tend to invite a lot of people so that they have to squeeze up, and that closeness makes for instant friendliness."

Going upstairs by the internal spiral staircase, which is set off by a painted panel of red on the wall, you reach the bedroom. Here a neat, narrow, white chest of drawers also bears Gabbertas's trademark, contrasting with the ornateness of the carved chairs that stand on either side of the grey upholstered headboard. "I think the chairs are Portuguese. They were my grandfather's. They're not really very useful in here, but I like them," admits Gabbertas. By the french windows leading to the upper terrace is a roughly hewn, green oak folding chair by Robert Kilvington.

At the front door, Gabbertas's coat hangs on a nifty hanger that slips into a steel wall socket, and he checks his attire in the adjacent hand-silvered Alice mirror. "The mirror is a mix of traditional hand-silvering techniques and high-tech waterjet precision cutting. I like the combination of old and new methods," he says.

Because the outdoor spaces are as important as the indoor ones, Gabbertas's work is on display in the garden areas, too. On the ground-floor terrace is a prototype for the seating he created for Tate Britain; on the upper deck are two lightweight BB chairs produced by Lloyd Loom; and in the small, cobbled courtyard is his most recent project: the hooded Eclipse lounger that's been nominated for the Grand Designs Magazine awards. Unfortunately, Gabbertas doesn't seem to have the time to give it a really thorough testing.

Gabbertas Furniture, Dawes Road Studios, 102 Dawes Road, London SW6 (020-7386 7385, www.gabbertas.com )

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