MOST families would welcome some extra living space. Moving house is one way to get it but the alternative is to extend or modify your existing house in some way.

This certainly represents the best value for money because almost every pound you spend adds to the value of the house. But it is a major project that needs careful planning.

There are many reasons for extending your home. The most obvious is to cope with an expanding family and extra possessions but you may wish to have more space to cater for hobbies or sporting interests or to accommodate an elderly relative.

The main options when it comes to creating more room for living are:

re-arranging space by changing the position of internal walls, for example, to create extra rooms; converting space by utilising a cellar, garage or loft for living space; adding space by building on to the house a conservatory, extension, garage or porch.

RE-ARRANGING SPACE:

If you live in a house with large rooms, you may be able to divide them up to create more rooms. An obvious example is a bedroom which can be divided into two small bedrooms, or an area partitioned off to create an en-suite bathroom.

Although this doesn't actually create more space, it will make the existing space more useful. Building the necessary plasterboard partition walls is in some ways the simplest part of the job: what needs more thought and planning is ensuring that both of the rooms have adequate heat, light and ventilation and that access to the two rooms is arranged as conveniently as possible.

CONVERTING SPACE:

The four main parts of a house which can be converted to more useful space are: outside WCs, cellars, attached garages and lofts.

An outside WC can often be used to enlarge a kitchen. As this will involve knocking out part of what is almost certainly a load-bearing wall, you will need professional help but the extra space could make all the difference to a cramped kitchen.

Whether or not you can convert a cellar to useful space depends mainly on how high it is.

Many cellars, particularly "old coal holes" have scarcely enough room to stand up in and digging out the floor is a major task which has to be done very carefully.

Converting the loft is the most fruitful way of creating extra space. In the majority of houses you can reckon to get two extra bedrooms or a bedroom and a bathroom. To do this, will probably mean strengthening the loft floor and modifying and extending the services, such as water, central heating and electricity and providing a proper staircase as well as roof windows.

You have the choice of using a specialist loft conversion firm or employing a builder to do the work, but either way, you may be able to do some of the finishing work yourself, leaving the experts to handle all of the major structural alterations.

All these conversions are likely to need building regulations approval.

ADDING MORE SPACE:

If the possibilities for re-arranging or conversion do not exist or are exhausted, you will have to think about adding on to the house by means of a porch, garage, conservatory or brick-built extension.

A porch is a relatively inexpensive way of adding space. It will provide somewhere to store coats, wellies and umbrellas or to keep plants in the winter and will also form a "buffer" between the house and the outside world which will then reduce the amount of heat escaping and the amount of noise getting in.

A brick-built extension is, of course, the ultimate in home enlargement.

Not only can it be built to blend in well with the rest of the house, if properly designed and built, it will add significantly to its value.

The most common brick-built extension is a new kitchen, with the existing kitchen being turned into a dining area or small sitting room: a two-storey extension can provide extra bedrooms and bathrooms, as well, either on top of a new kitchen or on top of a new garage, perhaps.

Once you have decided what you want to build and your architect or builder has produced detailed plans you must find out whether your proposals require planning permission, building regulations approval, or both.

To do this, contact your local authority planning department and Building Control Officer for preliminary discussions