HOUSEHOLDERS spend hundreds of millions of pounds on home improvements or repairs each year but when things go wrong the cost both in cash terms and stress to the individual can be devastating.

But the damage can be limited if the house owner takes some commonsense precautions before agreeing the work to be done, and if things still go wrong all is not lost!A large number of complaints arise about the trading practices of builders, and in many cases householders are dissatisfied with the outcome.

But guidance is available from The Office of Fair Trading, a Government department headed by the Director General of Fair Trading, which has a wide range of duties concerned with protecting consumers and encouraging competition.

This includes identifying and tackling trading practices which may adversely affect consumers' interests, whether they are anti-competitive practices in a whole sector of industry, or actions on the part of individual traders which mislead or deceive consumers.

For guidance on where practical help may be obtained if problems arise in the purchase of goods or services ring 0345 224499.

Calls are charged at local rates.

You can get advice from your local Citizens Advice Bureau, Consumer Advice Centre, or Trading Standards Department.

Anyone who would like a copy of the Office of Fair Trading's list of publications should write to The Office of Fair Trading, PO Box 2, Central Way, Feltham, Middlesex TW14 0TG (0181 398 3405).

The Office of Fair Trading offers advice designed to help the ordinary homeowner avoid some of the potential difficulties when employing companies or individuals to carry out work or improvements on your property.

Some of the typical complaints are: Being pressured into having unnecessary work done Over-charging Losing deposits paid to traders who turn out to be fly by nights Delays to work Work left unfinished when the contractor ceases trading Poor workmanship Difficulty in resolving disputes.

If you take a systematic approach to your building work, you can limit the probable causes for complaint.

In this area prevention is better than cure.

A systematic approach involving carrying out the following steps is suggested by the Office of Fair Trading: Planning what needs to be done Obtaining necessary approvals Short-listing potential contractors Choosing the quotation which offers the best value Agreeing a written contract Finding out about guarantee schemes, particularly those which are insurance-backed Paying in stages in order to keep control of the work Knowing what to do in the event of a dispute.

A summary of the correct steps to take is: make a plan of what you want done and don't be pressured into any unnecessary work or work you cannot afford; Get the necessary consents for your local authority and insurance company and discuss your plans with your neighbour, particularly if there are party structures.

Draw up a short list of firms that are reliable, obtain quotations based on detailed specifications, and compare price, conditions and reputation for reliability and good workmanship.

Get a written contract covering all the details of your agreement and find out whether a worthwhile guarantee is available giving cover against the contractor ceasing to trade.

Avoid deposits and advanced payments.

Use stage payments as a means of keeping the work progressing, and be as clear as possible about the way you will deal with any disputes.

If things do go wrong there are a number of steps you can take: after discussing the problem, give the trader a chance to put matters right, but if you are still not satisfied, put your complaint in writing, saying what you want done and setting a deadline.

Write to the head office if there is one.

Keep copies of letters, notes of conversations, photos, and a diary of events, if relevant.

It could be worth getting an expert opinion to back up your complaint.

Any reputable trader with relevant experience can count as an expert.

It may cost money but could be very useful if you need to take legal action.

Depending on the seriousness of the problem, think about withholding all or part of any further payments until the matter has been resolved.

Check your contract first.

In particular, be careful if you have a credit agreement as there may be problems if you fall behind with your payments.

If the contractor belongs to a trade association, there may be a conciliation or arbitration scheme which you could use.

You can take your contractor to court.

If the amount you are claiming is less than £1,000 you can use the small claims procedure.