Good day in the shed, darling?

Trying to find room for an office at home? The answer may be to broaden your horizons.

There are more than a few for whom going to work involves nothing more than getting up from the breakfast table and walking into another part of the house. Computer, phone and paperwork may occupy a bedroom, converted loft, stairwell or cellar. They may even be hidden in a stylish bit of furniture - a 21st century office version of the commode.

There are more than a few for whom going to work involves nothing more than getting up from the breakfast table and walking into another part of the house. Computer, phone and paperwork may occupy a bedroom, converted loft, stairwell or cellar. They may even be hidden in a stylish bit of furniture - a 21st century office version of the commode.

Unless it is a matter of moving into a home with a perfectly appointed study, some hard bargaining must usually be done before all the family agrees on a room to be used for work. Ideal is a place as far removed from domestic disorder as possible which, certainly in cities, narrows the field of choice. But for those people who have broadened their horizons to take in the garden, the possibility of a self-contained room beckons.

The chances are any half-way decent structure started life as a shed, and quite small gardens can support surprisingly large ones. The bottom of long urban gardens are often neglected, and something that runs its full width and is planted with climbers can end up enhancing a property.

The potential use of an outbuilding may not be immediately obvious to buyers. But as Giles and Beth Cook recognised when they bought their three-bedroom south London house three years ago, it is a feature well worth having. All they knew was they would not continue to use it as a sauna.

"We had plans to turn it into all sorts of things," says Beth. "But for the past year I have been working from home and it has become a brilliant office. It already had a loo and shower, so all we had to do was put in the cabling and fit cupboards, shelves and a desk."

As a personal organiser of other people's busy lives, she knows only too well the distractions of being at home. Her only temptations are the odd bit of pruning on the way to work. "Once I am ensconced in the office I am not disturbed by the telephone or the television. At the end of the day I can close the door on all the paperwork and mess and forget about it."

The Cooks' house is being sold for £345,000, of which roughly £10,000 accounts for the office, according to Giles Cook, of estate agents Foxtons. "It has proved irrelevant to some people, but it matters a great deal to the buyer. To get an extra bedroom which could be used as a study he would have to spend at least another £40,000 on a larger house in the same street."

There is a similar story in the flat market. A two-bedroom flat in Clapham with a studio room of more than 16ft by 11ft, where once the garden shed stood, is being sold for £265,000. To get a room of those dimensions would normally mean looking at three-bedroom houses from about £400,000. But, Douglas & Gordon, the selling agents, put a value of around £15,000 on the studio, keeping it within many people's budget.

In pricey Notting Hill, large old buildings often have a room on a half landing which, because of its position, cannot become an integral part of any apartment. Mark Chick, of estate agents Leslie Marsh, says at one time they may have been shared bathrooms. "Owners of the flat with the extra outside room quite often use it as a storage room and I have seen one turned into a dressing room. But an increasingly popular use is as an office."

On their books at present, at £290,000, is a one-bedroom flat in Alexander Street with an additional 8ft by 4ft room with a window on a half landing. A property with a spare bedroom-cum-office would be difficult to find without upgrading to a maisonette over two floors and costing around £550,000 to £600,000. "The one-bedroom flat plus is an economical way of getting the extra room. It is very important, though, that buyers check on the lease plan that the room is actually included. It could come as nasty shock at some later stage to find out that they do not in fact own it," adds Mr Chick.

In all price ranges and types of property the added value of an extra structure is not an exact science. In Clapham Old Town an end-of-terrace Victorian house has been priced separately at £495,000 from the mews house at the bottom of the garden at £275,000. James Robinson, of Douglas & Gordon, says the dividing wall could be knocked down to create one large garden with a family house at one end and further accommodation at the other. The two together have an asking price of £770,000, which does not include a premium that many would be prepared to pay for two connected properties in London.

It is not necessary to seek planning permission to knock down an outbuilding and start again provided it does not exceed the dimensions allowed under permitted development. Sheds and greenhouses can cover up to half the garden if they are less than three metres high for a flat roof and four metres for a ridged roof. Gideon Amos, of Planning Aid for London, a charity offering free advice, says it is important that building regulations are complied with and buyers should check when buying a property.

One of the more pressing issues facing families is how to find room for an au pair or elderly parents. It would be difficult to find a more unusual home than the old showman's caravan in the gardens of a farmhouse in Chantry, Somerset, being sold by Cluttons. The elderly lady who lived there into her 90s may have missed out on good plumbing but she had her own covered verandah - and the most romantic sheltered housing imaginable.

Planning Aid for London, which has just received a lottery grant for its work in giving communities a stronger voice in planning and development, 020 -7247 4900; Douglas & Gordon, 020-7228 5464; Leslie Marsh, 020-7221 4805.