These are only picked up in a full property survey, but just one in five buyers commissions one - despite the fact that both the Council of Mortgage Lenders and Consumers' Association both recommend their use.

A property survey can add to the costs of buying a home at a time when budgets are usually stretched quite tight, but as any surveyor will confirm, they can more than pay their way in the long term by picking up on costly problems that will require remedy in the future.

Faraz Baber, a RICS director, says: "People often think that a mortgage valuation is the same as a survey - it is not. Only a Homebuyer Survey and Valuation (HSV) report or a Building Survey, undertaken by a chartered surveyor, will give you the information you need to know about the structural health of the property you are about to buy and its value."

So how do you know whether to stay with a valuation report or to go for a property survey? The general rule of thumb is that any property erected before 1900, over three storeys high or with over 200 square metres of floor space should have a property survey, as should any that are unusual in construction, in poor repair or in need of renovation.

A FULL SURVEY

A full survey is also particularly worth having if you harbour any doubts about the condition of the property or are a novice buyer.

The survey should be carried out by a qualified person who specialises in this kind of work, such as a building surveyor or an architect.

A qualified surveyor may be a member of the Royal Institution of Chartered Surveyors (RICS), a body responsible for maintaining standards within the profession. RICS can provide the names of its members in a given area who are qualified building surveyors.

You should discuss with the surveyor how comprehensive a survey to carry out, and obtain written confirmation as to the extent of his inspection.

The extent of the survey will depend on the age and condition of the property - and on how much you can afford.

Fees are usually arranged by negotiation and relate to the time taken to inspect the property and write up the report.

Generally speaking, the larger the property - and the worse its condition - the more comprehensive the survey and the longer it will take.

BUILDING SURVEY

The most comprehensive type of property survey is a Building Survey, which is suitable for any buildings older than 150 years, or any that are unusually built, in a poor state of repair or in need of major renovation. It will cover:

- major and minor faults
- the implications and costs of remedying faults
- results of tests for dampness on walls
- recommendations for further investigations
- comments on any damage to timbers
- comments on damp-proofing, insulation and drainage
- likely costs of rebuilding in the event of damage
- technical information on the construction of the property
- information on the location.

HOMEBUYER SURVEY & VALUATION

For many buyers, such a comprehensive survey is unnecessary and in this case, the RICS recommends a Homebuyer Survey and Valuation (also known as HSV, or homebuyer report).

This type of survey is suitable for properties built within the last 150 years that are in reasonable condition. It's not a detailed or entirely comprehensive survey, but will cover:

- general condition
- major faults in accessible parts of the building
- urgent matters that need attention before contracts are exchanged
- results of tests for dampness on walls
- comments on any damage to timbers
- comments on damp-proofing, insulation and drainage
- likely costs of rebuilding in the event of damage
- the market value of the property.

Whichever survey is commissioned, the information gathered should be used to offer the seller a price that reflects the cost of putting the property in good structural order.

Should the seller refuse to negotiate, you are not obliged to proceed as long as your offer was made subject to survey and contract.

Some lenders also offer similar schemes which cost less than a structural survey and give more information about the state of the property than a basic valuation.

* RICS has recently published a guide to property surveys, which are available on-line at www.rics.org or by telephoning 0870 333 1600.