Unless you have enough savings in the bank this will require borrowing cash. Richard Mason, director of Moneysupermarket , says it depends on how quickly you intend paying the money back. When you are getting quotes from builders, it's worth adding an extra 15 per cent to cover any unforeseen problems.To decide whether it's worth building the extra room - or moving - you will need to compare the money required to buy the larger house and the moving expenses, with the construction and planning costs.You also need to decide how to pay for the work. As the cost of enlarging your home depends on a number of factors - such as location, the size of the project and the materials used - the estimates we quote are just for guidance.As well as the actual building costs - illustrated in more detail below - you will also have to pay for planning and legal fees, as well as the costs of employing architects and disposing of waste in a skip.

Are you planning to start a family and need an extra bedroom? Do you want an office to allow you to work from home? Have you always fancied having a mini-gym?If you are looking to expand purely to increase the value of your property, you need to be careful to ensure your plans are cost-effective. "This also means they can avoid having to move and pay expensive stamp duty and agents' fees."Start with a dose of realism You need to decide exactly what you want from the project. "At these levels people are thinking seriously about extending or converting a basement or loft which can be more cost-effective than moving."A spokeswoman for the Royal Institution of Chartered Surveyors agrees that many people are looking to carry out major home improvements rather than go through the stressful and expensive process of finding a new place to live."People are extending outwards, upwards and downwards to improve the property they own," she says. And even though this predicted increase is far less than the 30 per cent hikes witnessed at the height of the property boom a few years ago, it still means that moving house is likely to become even more expensive over the coming months. A study published by the Woolwich this week revealed the cost of moving from an average £174,744 semi to a detached home worth £293,248 is £12,535 - up from £4,535 six years ago.Andy Gray, head of mortgages for the Woolwich, says this huge rise can largely be attributed to house price inflation pushing an increasing number of detached properties through the Government's 3 per cent stamp duty threshold of £250,000 - trebling tax bills in the process."At the top end of the market, people are getting unsettled by headline numbers like £25,000 to move up from a semi to a detached," he says. House prices are rising again - and it's posing a dilemma for homeowners in need of extra space: can they afford to move somewhere bigger or should they add extra rooms to their existing property? The average UK house is expected to increase in value by 6 per cent over the coming year, according to website Propertyforecasts.co.uk. They also need to ban junk-food advertising to kids and find more ways of encouraging people to exercise."Caroline Flint, the Public Health minister, said the Government would continue working "to meet our target to halt the increase of childhood obesity by 2010".. We are in danger of raising a generation of people who have a shorter life expectancy than their parents."Amanda Eden, care adviser at Diabetes UK, said: "A firmer line needs to be taken to force the food industry to adhere to labelling guidelines so people know what's in the food they buy.

He said: "It augurs badly for the future health of the population. The number of obese men has almost doubled since 1993 - from 13 per cent to 24 per cent in 2004. For women, the figure has gone from 16 per cent in 1993 to 24 per cent in 2004.But the survey also shows that number of men eating at least five portions of fruit and vegetables a day increased from 22 per cent in 2001 to 24 per cent in 2004, while the figure for women went from 25 per cent to 27 per cent. The number of men exercising for 30 minutes, five or more times a week, increased from 32 per cent to 35 per cent between 1997 and 2004, and from 21 per of women to 24 per cent during the same period.Professor Colin Waine, chairman of the National Obesity Forum, said the figures revealed a "public health time bomb" because research showed that 11 to 15-year-old children who are obese are twice as likely to die by the age of 50.