Modern master: Architect John Pawson reveals his life-long love affair with the perfect monastic space

Pawson shows Caroline Roux around his latest client's minimalist home

The exhibition currently occupying the top floor of London's Design Museum is an exquisitely curated affair. On one 13m-long table are neatly aligned books and documents; an entire gallery wall is hung with photographs of perfectly appointed contemporary homes, be they a steel-roofed rural retreat in Sweden or a white block slotted into a Moroccan medina; models of small buildings show an elimination of decoration and a love of pure graphic form, whether it's an apartment block or a bridge sweeping through Kew Gardens; a sustainably grown tree has been imported from Germany and sliced into exact segments. It is, then, what you might expect from a show of Minimalism's most-famous exponent, the architect John Pawson, whose name is now synonymous with the most pared-down perfection.

Pawson's own house has had much attention for its wide open spaces and incredible lack of clutter, where every essential artefact is hidden behind the endless cupboard doors and even books go unseen. The only paint colour he knows is white; materials are taken from a palette of limestone, oak, granite, concrete and little else. He's applied the aesthetic to many other buildings, including Calvin Klein's major stores and, more surprisingly, a Cistercian monastery at Novy Dvur in the Czech Republic (the monks saw a picture of the Calvin Klein flagship on Madison Avenue in New York and knew they'd found their man). When he was asked by the upmarket Belgian tableware company When Objects Work to design some cutlery, he in turn thought about what would look right in the monastery and designed the most streamlined implements imaginable. For another project for the same company, he created the five objects that he considers to be the only decorative ones needed in a home: a bowl, a vase, a picture frame, a candlestick and a tray.

There are, of course, plenty of people who throw up their hands in horror at the idea of a life without cushions, carpets, ornaments and lampshades. But there are more than enough takers to keep the architect very busy indeed. Even the occasionally rococo Karl Lagerfeld discussed a project at length with Pawson –"I hate everything round, that is my problem. I only like square rooms, gardens," he declares in one hand-penned letter, before going on to say that ponds and tables can be round at a pinch. You can't help thinking that his and Pawson's pernickety attention to detail would have been well suited.

In a world of way too much information, though, coming home to an eerily empty Pawson house could be what many of us need. That's the opinion of Daniela de Camaret, a Brazilian journalist who has been living the complete Pawson experience for five years. "Just before I moved in, I freaked out," says De Camaret, perched on the arm of an angular (Pawson-selected) redwood chair, originally designed by the American architect Rudolph Schindler in the 1930s. "And when my mother heard about the sort of place I was moving into, she was really worried. How can you live without even a flower vase? But now I think that if you have the chance to live like this, it's life-changing."

If that's sounds extreme, consider the facts. De Camaret's books are now all in Brazil. She has only one piece of art on the walls – an appropriately restrained piece by the celebrated American artist Robert Ryman that consists of 20 white rectangles that run round adjoining walls. There is just one gorgeous orchid in each room. There is limestone as far the eye can see, even in the back garden – a paved square planted with four perfect cherry trees (each with a different shimmering metallic-looking bark). In the kitchen, one white bowl of matching red apples sits on an uninterrupted work surface. The bathrooms look like they have never been used. You certainly need a lot of discipline to live like this: there is not a coat or bag or magazine in sight. "But," says De Camaret, "there's something exciting about getting rid of everything you don't need – purifying." The only things she holds on to, it turns out, are clothes. "And not because it's couture or anything. Nice old cotton things – I can't throw them out."

De Camaret hadn't intended to take up the minimalist mantra. She had been to Pawson's own home for dinner (they met through their children) and admired his sons' shower room with its window in the ceiling. But then, with her ex-husband, she found a house to buy in Chelsea and it needed a bit of help. Built in the 1980s in a postmodern faux-historic style and lavishly furnished in French-type décor (lots of highly polished wood and striped, swagged curtains), the location was the only perfect thing. "I picked up a magazine, and there was a picture of John and his phone number. We told him it had to be done in a year," she says.

It would be easy to assume it's Pawson who lays down the law in such circumstances. In reality, he comes armed only with his very specific aesthetic, and it is the client's needs that come first. "As an architect, you're making rooms and buildings based on someone's life. It's not about me," he says, now in his 60th year and dressed in a soft grey cashmere sweater and dark grey trousers. "The idea is that every room should be comfortable. Not one space should be less than perfect." Bearing in mind that De Camaret's house spreads over four generous floors and she says she uses every part equally, in this case he seems to have got it about right.

When he first visited the house with his new clients, it was winter and no one could find the electricity switch. "So we looked around in semi-darkness," says De Camaret. "We couldn't see any details, we could only get the feel of the spaces. We talked about what we wanted for a family home [she has two sons now aged 17 and 23] and he said: 'Give me a month'. I thought – is that it? But John's a minimalist in all things, even meetings. A month later, he came back with a plan." Her only specification had been that the stairs should be the same size, but she needn't have worried. Pawson is known for his rigorous flights of matching steps that often ascend through canyon-like spaces in his buildings.

While many would never describe this as a family house, the boys' own rooms looked lived-in enough, though all gadgets and books are in concealed shelving placed behind the wall behind the bed. There is a sleek dining room filled with Hans Wegner furniture that looks rather less used, but the large relaxed living room on the lower ground, that looks out at a swimming pool, lined in black tiles to make it reflective like a mirror, feels warm and cosy. The whole house is flooded with light. "It's like being on holiday all the time," says De Camaret. "Children love these kinds of spaces," adds Pawson, who also has two sons now aged 19 and 21. "Caius [who now manages the band du jour The xx] used to skateboard all over our ground floor."

The complexity of the house, of course, is everything you don't see. This is an architecture where electricity, cabling, heating, even speakers, are unseen. "But John's minimalism is one that still ticks all the boxes for living," says De Camaret. "And he's translated the way I like to live better than I could. We discussed everything, and there was nothing we couldn't reconcile."

Well, almost nothing. Pawson's preferences are monastic, even down to his liking complete silence. "One thing about me won't ever change," says his client. "He can have his silence. But I'm Brazilian. I'm not giving up my samba any day soon."

John Pawson: A life's work

Born: Halifax in 1949

Educated: Eton and the Architectural Association

Family: married to Catherine. Two sons Caius and Benedict

Formative experience: travelling through Japan and working in the studio of master architect and designer Shiro Kuramata

Inspiration: the work of American artist Donald Judd

First commission: a minimalist apartment for his then girlfriend Hester Van Royen. It was publicised widely and immediately established his reputation

Subsequent work: apartments and houses for clients including Bruce Chatwin, photographer Cindy Palmano, creative director Fabien Baron, art collector Doris Lockhart Saatchi, model Natalia Vodianova and Justin Portman. Pawson has designed art galleries in Dublin, London and New York and fashion stores for Calvin Klein and Jigsaw all over the world

Currently working on: projects currently underway include a ballet set for the Bastille Opéra in Paris, a hotel in Jaffa, a new system for Bulthaup, a boathouse in Gloucestershire, a house on the edge of the North Yorkshire Moors, a house looking out to sea on the Japanese island of Okinawa, a fully sustainable house near Treviso in northern Italy and the possible transformation of the former Commonwealth Institute into a new permanent home for the Design Museum

Published works: include 'John Pawson Plain Space' by Alison Morris is published by Phaidon (£45)

John Pawson – Plain Space is at the Design Museum, London SE1 until 30 January 2011.