YOU'VE spotted a property that looks ripe for renovation - but how do you decide whether it has true potential or if it's going to be a millstone around your neck?

Knowing the cracks in the walls that have put other buyers off can be fixed easily and may mean you get hold of a bargain.

It's also important to know when it is best to walk away from a house that looks a bargain but could turn into a money pit.

To help you decide whether that house you've fallen in love with is a good buy or a bad buy, organisers of The Homebuilding & Renovating Shows have some useful tips:

Cracks - Are they structural or cosmetic? Cracks in plaster walls and masonry can look worrying but are frequently only cosmetic. Being able to tell them apart from the symptoms of more serious structural problems can be useful in making your verdict on a renovation project.

Cracks in materials that are isolated, eg a crack in a single brick or a stress crack in a plaster wall adjacent to a window or doorway, are unlikely to be structural.

Where the cracking is more extensive and follows a pattern ie a crack running through a series of bricks, there is likely to be a more serious cause. Look for signs of movement in the building. Typical causes are subsidence (which may mean underpinning beneath the walls) or the failure of the floor or roof structure. In a very old building, however, the structure may be perfectly stable despite twists, bows and warps and attempts at repairs may do more harm than good.

Signs of Damp in Walls of Floors - Old buildings without damp are the exception; so don't be too concerned about signs of damp as they can always be solved. You need to identify the source of the damp and, once discovered, solving it involves simple and inexpensive repair or replacement.

In an old brick building, a damp proof course can be created by injecting silicone into the bricks both inside and outside the building. For the average terraced house, this will cost around £300-£400 plus the cost of redecorating.

Rewiring - Tell tale signs that a house is in need of rewiring are easy to spot. Look for an old-fashioned fuse box instead of a modern consumer unit, old fashioned round light switches, round pin plugs or old wires. Rewiring a typical three bedroom terraced house costs from £2,500 to £3,000, including removing the old wiring, lifting and replacing the floorboards and installing a new consumer unit.

Central Heating - Adding central heating is easily one of the most cost-effective improvements you can make to a house and will always add more to the value of a property than it costs to install. Adding a wet radiator, gas central heating system to a typical three bedroom terrace house will cost £2,500-£5,000.

No upstairs bathroom - Many old houses were built either without bathroom facilities or have since had them added on the ground floor. Installing a new bathroom at first floor level is likely to cost around £800-£1000, with a basic white bathroom set from one of the DIY stores costing around £250-£350. Creating the stud walling for a new bathroom out of an upstairs bedroom is likely to cost £1,5000-£2,500 including finishing and tiling, but consider the implications of possibly losing a bedroom to make space for a new bathroom.

Dry Rot - Dry rot is a fungus that destroys timber very quickly. It loves moist, poorly ventilated conditions and is usually found in the roofspace or under wooden floorboards. The first sign of dry root is often its distinctive musty smell when you lift a floorboard or even just the carpet. Getting rid of dry rot will cost around £1,000 for treatment by a specialist firm.

Woodworm - Woodworm is a common pest in damp timber that can cause major problems. However, in most situations the damage is superficial and the problem can be eradicated using pesticides. The problem can be more serious if the woodworm gets into less accessible areas of the structure that cannot easily be treated. Pesticide treatment costs from £600 - £1,000 for an average house.

Windows Require Replacing - Replace your original windows with caution, as they can be an inherent part of the building's character. Original windows can often be repaired and this may cost less than replacing them with new windows. In many areas, however, replacement windows are a must for all buyers and will add considerably more to the value of the property than they cost.

Do your homework - Get as much information as possible by buying specialist magazines, or visit one of the series of Homebuilding & Renovating Shows taking place around the country. The next show is the Northern Homebuilding & Renovating Show at the International Centre, Harrogate from November 12 to 14. For more information, visit www.homebuildingshow.co.uk or for tickets call 0870 010 9031.

q Target is giving readers the chance to win one of five pairs of tickets to the Northern Homebuilding & Renovating Show at the International Centre in Harrogate.

For your chance to win a pair, simply write your name and address on a postcard and send to: Target/Homebuilding giveaway, Globe House, Catherine Street, Birkenhead, Wirral CH41 6HW by the closing date of November 3.