Property: Nice flat - shame about the DIY

The house is yours, you have bought a screwdriver, you are itching to join the national craze for home improvement. Then you remember that your home is the costliest asset you will ever own. You will probably want to sell it one day. Make the right choices and DIY can pay for itself by adding to your property's value. Get it wrong and future buyers may be hard to find.

Home improvement is not an exact science but Ekins Surveyors, which acts for the Woolwich, has produced a scoring system to show which work adds most value. Ignore it at your peril.

"The first question you must ask yourself is whether you are nesting or investing," says Paul Wildman of Ekins. "If you are staying for a long time, go for it, but if you are thinking of selling within the next five to 10 years, consider the impact on the potential buyer."

Another problem is deciding which styles will endure - and which will have all the long-term appeal of a 1970s pine kitchen. The simplest rule of thumb is to make sure your decoration fits the period of your home. Also be wary of the hyper-fashionable - glass bricks are already looking dated.

KITCHEN

We use the kitchen to cook, argue, and all the best parties end up there. You can easily spend between pounds 6,000 and pounds 15,000 on a new one, says Paul Wildman, but it is money well spent. "If you can afford it go for quality, because it will survive the wear and tear better. Buy prestigious brands for the oven and appliances," he says.

Plain, streamlined appearances are fashionable and this is partly because simple, high-quality materials will not date as fast as the cheap, gaudy or quirky. Go for natural surfaces such as lava stone and granite, beech, stainless steel or slate. If you cannot afford a full refurb you could paint the doors on kitchen cupboards or replace them at a fraction of the price.

Peter Barkham, 50, an interior designer with Barkham Interiors in Blackheath, south-east London, is spending pounds 15,000 installing a "simple but not minimalist" kitchen in his three-bedroom Victorian flat. "I have always liked to live in a nice home. I am not looking to make a profit on the work, but I will get my money back." He didn't consider a cheaper option: "I don't want to carry my kitchen through Ikea on a trolley and spend my spare time messing around with screws."

Value factor: 7/10

BATHROOM

Barkham is spending pounds 9,000 on his new "modern classic" bathroom. He says kitchens and bathrooms are the major attractions in a house. "They are what people look for when buying." Wildman agrees: "The fittings are relatively cheap - as little as pounds 400 from DIY chains. The main expense is the plumber to install them. Doing up your bathroom has an immediate impact."

If you have a large family and the space, he suggests installing a second bathroom. To make a small bathroom appear bigger, use mirror tiles and light colours. Just remember that there's only one colour when choosing your suite - it has to be white.

Value factor: 7/10

WINDOWS

Not everybody slams the phone down on those salesmen who call during EastEnders, because one UK window in five now boasts double-glazing. They cut fuel bills by providing extra insulation. "If you live on a busy road they could be worth their weight in gold," says Barkham. A new set of windows will cost around pounds 2,500 for the average house, including a new front door (don't forget this). "It is a very competitive market so shop around and go for somebody who is a member of a professional trading body. New windows are generally a good investment."

You should make sure the windows suit your property, and always have at least one on the first floor wide enough to escape through in case of fire. But beware replacing wooden windows with uPVC, which can be a style disaster in a period home - they may actually reduce the value of your home. Never mix and match.

Value factor: 5/10

DECORATION

Everybody knows what a quick lick of paint can do. "It is relatively cheap but has a big effect," says Wildman. One of his clients, still hankering after her hippy youth, found no takers when she put her house on the market with every wall painted purple or black. "Redecorating cost her pounds 100 a room but added pounds 5,000 to the price." For maximum re-sell value, he says, remember the maxim "bland is grand". New homes are usually painted magnolia or white. I bought a house recently. Every time my girlfriend suggests we paint another room green, turquoise or bright yellow I cringe, imagining thousands tumbling off the resale value.

Value factor: 6/10

LOFT CONVERSION

When Amanda Hall, 31, and her husband Nick, 32, converted the loft in their two-bedroom house in Redhill, Surrey, they were looking for an extra bedroom for their daughter rather than hoping to turn a profit. Nevertheless, aesthetics were a prime consideration. "We ruled out dormer windows, which give you more space but look like you have a shoebox strapped to your roof, and went for a skylight instead. They look better and let in more light," says Amanda. They spent pounds 13,000, but larger lofts could cost up to pounds 17,000.

After the work was done they asked a local estate agent to value the property as a two-bedroom house, and were told it would fetch around pounds 120,000. Then they showed the agent the loft, and the estimate jumped to more than pounds 140,000. "We didn't do it to make money - we expected to lose at least pounds 3,000 - we did it for the space."

Surprisingly, lofts score poorly on the Ekins scale. "They are expensive and if done badly can even reduce your selling price. They can also harm your street by breaking up its uniformity," says Wildman.

Econoloft, the company that converted the Hall's loft, is based in Ashton- in-Makerfield, Lancashire, but does 90 per cent of its work in London. This is significant. Where space is tight and house prices high a loft can add value, but if local prices and demand are lower do it only if you need the space.

Value factor: 3/10

EXTENSION

While loft extensions should be treated with caution, added rooms on the ground floor are a much more attractive proposition. For a start they are cheaper, partly because access is easier for builders, and they also give you far more options. You can use them as a dining room, conservatory or simply extra living space. Where property prices are high an extension will add more value, but only if the builders do a good job and are sensitive to your original home and street. We have all seen extensions that look like a truck has just driven into the side of the house. Prices can start at around pounds 5,000 - a good rule of thumb is pounds 50 per square foot, says Wildman. Watch out for cowboy builders, he adds - take recommendations from friends where possible. For an ambitious project consider employing an architect or surveyor. A kitchen can never be too big. An extended dining area will add thousands to your home.

Value factor: 6/10

CENTRAL HEATING

One job above all that must be done. If your home does not have central heating, installing it should be a priority. "It was a luxury once but is now a basic need," says Wildman. "You will probably have a problem selling your home without it." Installation costs around pounds 2,500 for a three-bed semi but you should easily recoup that when you move. If you are putting radiators in, do so before you do any other decorating, as you are likely to damage the paintwork or wallpaper.

Value factor: 10/10

Finally, remember that while selling on is important, this is your home, so don't become too obsessed with the needs of future buyers. You never know - some may have exactly the same warped taste as you.