Basements aren't always the most inviting places in a home. In their natural state, they're often damp, dark and - as horror film fans will know - full of things that go bump in the night.

But a basement or cellar can be converted into a comfortable and cosy room, making it a great way to maximise the space in your home.

As house prices continue to rise, many people find that moving to a bigger house is not necessarily the most economical way to get more living space.

But while, traditionally, people have expanded their homes sideways with extensions, or upwards into the loft, for those with the right kind of property, basement conversions are becoming increasingly popular. Creating extra space in the basement gives you the opportunity that wouldn't be possible with a loft conversion.

Having a solid floor means you could install heavy home gym equipment, a full size snooker table or, for really big spaces, you could even squeeze in a swimming pool.

However, basement conversions are most often used to add extra living space, perhaps as a kitchen, family room or playroom for the children.

Converting a basement also has a positive environmental impact, extending the building within its exisiting footprint and maximising the use of land.

Basements are also naturally well insulated, reducing energy wastage and can even help warm the rest of the house from below.

Even properties without basements or cellars can have space created, although unsurprisingly this doesn't come cheap and excavating this new room could cost considerably more than converting an exisiting space. Basement conversions also bring about their own challenges from a structural point of view.

Many Victorian properties, which tend to have existing basements or cellars, also have quite shallow foundations which may require underpinning before any conversion may be done.

It is vital to take advice from specialists such as structural engineers, architects and builders before doing any work, as well as ensuring you have any necessary planning permission.

If you are spreading downwards, there will always be concern about dampness and ventilation, as well as heating and light.

One technique, known as tanking', lines the basement with a metal skin, preventing water penetrating the walls. This is then plastered over the top to create the walls of the room.

Once the walls are sealed, it is also vital to put in the right ventilation to prevent the build-up of condensation, and to allow fresh air to circulate.

Natural light can be hard to come by, but can make a great deal of difference to the look and feel of the space.

Where this isn't possible, partially-glazed doors or glass bricks can be an effective way to let light in from other parts of the house.

Going underground isn't always the cheapest option and, in the majority of cases, it probably isn't the easiest, but a basement conversion can add considerable value, adding up to 20 per cent to the value of your property.

So although the initial cost is likely to be high, it could prove to be a good long-term investment, and if you decide to sell, potential buyers should love it.

To find out more, The Basement Information Centre has some useful contacts and information. Visit www.basements.org.uk