Have you got room for one more on top?

Short of space for a bed? Forget that costly loft conversion. As Sonia Purnell discovers, architects and home owners alike are discovering the discreet charm of sleeping platforms

Sean Ellis's new hi-tech flat was once the school badminton hall in a grand old converted building on the edge of Victoria Park in east London.

When he bought it three years ago, the Edwardian fruitwood floor still had its original spring and was marked out with white court lines. But much of the charm – and the natural light on the lower floor where there are no windows – had been destroyed by the first developers who had unimaginatively turned an impressive lofty space into a rather boring two-storey box.

Mr Ellis, a successful photographer, and his architects, Azman Owens, took a year to gut the flat, reclaiming at least some of the 35ft ceiling by cutting away the first-floor bedroom to form a higher, smaller but spectacular sleeping platform.

Reached by two flights of steel-coated stairs – "WD40 and an emery board work wonders on keeping them clean," Mr Ellis says – the platform is open save for a waist-high glass parapet on one side and a huge bookcase reaching right up from the sitting room, on the other.

Light can now stream down directly from the part-glazed roof into the sitting room far below or through an enormous clear-glass panel in the platform floor. Some 14ft long, the glass was so heavy it took 20 men to lift it, but unfortunately it cracked in the process and had to be cut in two.

Yet despite all the glass and the lack of solid walls, the platform feels intensely private from the rest of the apartment, not least because it hangs 25ft high in the air. "I used to live in a really noisy flat in Old Street, and the constant traffic used to drive me mad," Mr Ellis says. "But the first night I slept up here it was such a relief. There's an incredible feeling of peace."

The platform is level with a new roof-terrace, commanding views to the west, of Centre Point and the BT Tower, as well as the decorative stone urns on the old school roof. Down one flight of stairs to the rear of the apartment is the bathroom, set on another platform but cordoned off by a wall of cupboards housing Mr Ellis's precisely arranged collection of 75 pairs of (mostly Adidas) trainers.

Behind the wall and sited directly above the kitchen is the bath, complete with underwater lighting. Cut into the kitchen ceiling like a conventional skylight, the bath is made entirely of clear glass (yes, really), again aimed at maximising light into the space below. But when in use it can still prove a somewhat alarming feature for unsuspecting guests.

"It's a bit like a luminous cage," Mr Ellis says. "Friends don't really want to come round here for a bath, knowing they'll be on full view to anyone in the kitchen. They're good friends, but not that good."

In another recent conversion – of a former piano factory in Peckham, south London – the study had to double as a guest room, creating a jumble of office equipment, a sofa bed, and cupboards for the owners' shoe collection and work paraphernalia. A narrow room with high ceilings, it felt cramped and uninviting but was transformed with a custom-made desk and tall cupboards supporting a sleeping platform.

Ia Hjarrde, of Dive Architects, says: "We created a narrow stairway up to the sleeping shelf, which is so large it carries a bed one and a half metres wide on it. It's a lot more comfortable and separate for guests than the old sofa bed arrangements. Now with tall, custom-made cupboards for the owners' things – including a special storage cupboard under the stairs for golf clubs – the room feels more spacious and calm and the proportions work better too."

But while the high ceilings of loft spaces may provide the perfect conditions for a sleeping platform, with a bit of creative thinking, it is possible to carve much-needed extra space out of an ordinary house. Many classic British townhouses have plenty of loft space over their bedrooms that could easily be converted into a simple platform, accessible via a ladder. It's far less expensive than a traditional loft conversion, which in any case may not be possible in all houses; earlier Victorian houses frequently do not have enough loft space to create another floor. But where they are possible, the minimum cost is likely to be £25,000 to £30,000 and a full loft conversion take far more time to build than a platform. Building standards are much tougher too, particularly on the type of staircase used and fire regulations and you are likely to need to get planning permission.

The usual method for creating a sleeping platform under the eaves is to support the platform using built-in steel beams (at a cost of between £5,000 and £10,000 and you should seek the advice of a structural engineer before starting) but an increasingly popular option is to build cupboards or tall chests of drawers underneath, with special handles-cum-rungs to climb, rather than a conventional ladder.

The 10ft sq platform already built in the smallest bedroom in Rowena Gedye's early Victorian terraced house in West London was among the key factors in her deciding to buy the property 18 months ago.

Now occupied by her 10-year-old son Ben, it provides him with a fun sleeping area in the eves while leaving the lower space free for play and study. Mrs Gedye says: "It was a particularly clever use of space, tucked away like that and meant that while my daughter got the bigger room Ben got something that is both fun and rather boyish. We've even talked about him having a rope ladder up to it so he can draw it up and be in his own little castle in the sky."

The platform, at present reached by a wooden ladder through a hatch opening at one end, spreads out into the loft space over his sister's bedroom next door and partly over his own room, and is big enough for a double bed, chest of drawers and capacious storage. There is even enough room for a friend to stay on a sleep-over. And although walking upright is not possible, Ben can comfortably sit up in bed or on cushions on the floor.

"He stores all his most precious things up there, but there is still room for a suitcase or two of mine under the front eaves," Mrs Gedye adds. Ben says: "It's my exclusive little hideaway where I can express all my thoughts. I've got all my best stuff in it."

In the Gedyes case, steel wires, rather than a conventional balustrade that might have looked obtrusive, are strung across the edge for safety. Steel or wood guard rails are also popular, as is thick glass sheeting for a more contemporary look, although a short stretch can cost £500 even before installation.

The ceiling has been raised to the roof line in the whole room, not just over the bed, where a large skylight has been cut into the roof, but over Ben's desk in front of the window. That way the whole room feels airy, light and spacious. The ceiling has been insulated to keep it warm in the winter and cool in the summer.

The previous owners used the platform for their au-pair, providing private sleeping and sitting quarters without intruding on the family. Before that, a teenage girl slept on the platform, which she adorned with fur rugs, opulent cushions and, eventually, her boyfriend.

Azman Owens 020-7739 8191

Dive architects 020-7407 0955