"As soon as you mention lofts in Clerkenwell, everyone thinks of fashionable thirtysomething professionals," says Bobbi Carter. She and her husband Richard are challenging such assumptions with their new penthouse, which is in a converted Thirties Clerkenwell factory. For them, low-maintenance minimalism and proximity to the West End add up to "a perfect retirement home". Although both are only in their mid-50s and still working - she a solicitor, he an academic economist - this will be their last move.
As lovers of modern design usually find out, the words "children" and "minimalism" are a contradiction in terms. Bikes and buggies don't fit in. "The main advantage older people have in loft living is that they don't have young children," says architect Celia Maxwell Scott, who designed the Carters' interior. "And they can often afford the larger, more expensive spaces with better views, bigger terraces and more room for the storage of a lifetime of accumulated possessions." At Manhattan Lofts, London's largest loft conversion company, Harry Downes estimates that 30 per cent of sales are to people in their late 40s and older whose children have left home.
"We're just not country house people," says Bobbi. With the children gone, and after 20 years of family life in tall Victorian houses with gardens, the Carters listed what they really wanted from the rest of their lives - music, modern art and fine food and wines. They wanted to be just a short taxi ride away from London's best theatres, art galleries and restaurants. Other priorities were plenty of wall space to display their collection of modern art, good entertaining and cooking space (plus storage for wine). They also wanted a home where they could talk to each other without difficulty.
"In our previous houses, one of us would be cooking in the basement and the other would be four floors up in a study," explains Bobbi. "Finally, it was very important for me to hear music easily anywhere in the house. I was sick of either having lots of different equipment and wires all over the place, or trooping up two flights to put the music on."
The corner penthouse apartment they fell in love with was then "just a double-height shell, peppered with ugly pillars and featuring an enormous curved wall of glass wrapped round two sides". But it had fantastic light and space. They employed architect Celia Maxwell Scott to design it as one open-plan space with a mezzanine floor and a single, conventional guest bedroom (the only room with walls) tucked away at one side.
The sweeping, curved glass wall was the starting point, and, to keep the look clean and uncluttered, Scott's first task was to get rid of the pillars holding up the roof and mezzanine. "They are now held in place by a cantilevered design attached to the roof," she says. She also designed the mezzanine floor to follow the curved lines of the main window.
Allocating areas to specific functions was the next task - not always easy if you are faced with a completely blank space and a lack of a conventional "house" structure. The main door is on the higher level, and there is always a natural instinct to place the kitchen on the "ground" floor. However, Scott pointed out that because of rubbish and shopping, it should be as close to the front door as possible.
"Once we'd worked out where to put the kitchen, everything else fell into place naturally," she says. Now the kitchen-dining area, a temperature- controlled wine store, the spare bedroom and a tiny, wedge-shaped shower room for guests are all on the mezzanine, leaving the whole of the ground floor one big living space, with a small slice at one side for a study.
This wide-open space is only broken up by a storage unit which screens a large double bed, but the space flows freely on either side of the bed towards walls fully lined with almost-invisible fitted cupboards. "We had a big clear-out when we moved, but we're just beginning to accumulate things again," Bobbi says. "Richard isn't naturally tidy but having everything so open-plan has improved his habits." It helps to have a big double bathroom, a utility room and a general store-room all tucked away out of sight, although Bobbi worries that they are turning into giant dumping grounds.
Bobbi was determined that walls, floors, fixtures and fittings should all be black or white. The kitchen worktops are either stained black beech (the hard-wearing kind used in laboratories) or black slate, and in the main living area, they opted for a white vinyl floor with virtually indestructible black rubber flooring for the mezzanine. Light reflects off the white walls and floors so powerfully that Bobbi says she has had to throw out a lot of her clothes: "All those little marks and stains that you never notice in a dark Victorian house suddenly seemed to shout."
In the bedroom and study, there are black venetian blinds, but the main living window is far too large a space for blinds or curtains. "It's only in Britain that people worry about being overlooked," says Bobbi, who is pleased by the stunning skyline, crowded with other roof conversions, offices and flats, that opens out in front of them. "In New York (she is American), people can see into each other's flats the whole time, and it doesn't bother them."
They also radically re-thought their furnishing needs - did they really need sofas? They looked at countless makes, and then Richard discovered these brightly coloured Wink loungers from Geoffrey Drayton Interiors. "Most of the time, we're here on our own," Bobbi says, "and these are much more comfortable for two people. And when we need more seating, there's a stack of coloured upright chairs, which are much better than sofas if you have eight or 10 people in the room."
A room virtually without walls or furniture requires technical ingenuity - as well as underfloor central heating and cantilevered construction. Scott had the flat "future proofed", installing concealed wiring for computers, cable television and hi-fl sound, with speakers in the ceiling, so that music seems to pour out of the air at the touch of a button. "The rubber floor really seems to improve the acoustics." Friends who have chosen to turn their backs on urban living as they grow older seem genuinely envious at how comfortable and striking the whole flat is, reports Bobbi, "although one thought we needed a giant plant and gave us her 20ft high Ficus Benjamina, which was too big for her conservatory in Wiltshire. She crammed it into the car and brought it up to Clerkenwell. It's called Daphne and has so much character we couldn't be without it now."
Facts and figures
* Maxwell Scott architects can be contacted on 0171 485 2689
* Lofts in up-and-coming London: Shells in Bankside, near Blackfriars, range from pounds 120,000 to pounds 600,000 from The Manhattan Loft Company (0171 631 1888). At Canada Wharf, Rotherhithe, prices start at pounds 72,500 and reach pounds 375,000 from Metropolis Developments (0171 234 0288). To develop these shells can cost anything from pounds 15,000 to pounds 100,000 and up.
*Wink reclining chairs, designed by Toshiyuki Kita, which open up to a lounger and flip close to an armchair, are available in a variety of colours at pounds 1345 each, plus pounds 282 for washable overcovers, from Geoffrey Drayton Interiors (0171 387 5840)
* Rubber floors are increasingly popular - they're virtually dirt-repellent and stain-resistant, easy to clean, and hard-wearing (25+ years is common). Freudenberg's Nora range, the largest selection in the UK, is eco-friendly (no PVC or plasticisers), and has 200 colours in 16 designs. Call 01455 553081 for stockists and recommended fitters. Plain Noraplan costs pounds 15- 17 per square metre, plus fitting costs
* Open plan living demands quiet appliances. Extractor fans are particularly important to prevent cooking smells from pervading living and sleeping areas. The Carters used an Atag Profiair (O1275 877301) stainless steel canopy with an extra powerful roof-mounted motor for maximum extraction with minimum noise. The Profiair range has motors that can be situated in the attic, garage, roof or outside wall for quiet acfion. Prices for canopies, motors and fitting about pounds 1,OOO-pounds 3,000
* Marble adds luxury - at a price. Marble tiles, used in the Carter's kitchen, are much cheaper. B&Q has Ismir beige marble tiles at pounds 8.99 for 7
* The Carters keep a stack of coloured chairs for guests. Several designs of stackable coloured chairs are available from SCP Ltd (0171 739 1869) such as The Rondo (pounds 76 +VAT in 20 colours). Also try Viaduct (0171 278 8456) for styles including the Jacobsen chair at pounds 144+VAT (16 colours available). Both deliver nationwide