How to turn a cluttered garage into a living room with va-va-voome

Is yours filled with old boxes and rusting bikes? Jonathan Christie gears up for the latest property trend – converting the garage

So, when was the last time you actually parked your car in the garage? Even if you do manage to squeeze past the old tins of paint and carpet offcuts, you'll probably only be able to open the driver's door 12 inches before it hits the washing machine. Cars have got bigger; garages have become dumping grounds for all the detritus of modern life.

Meanwhile, the living quarters of the house are bursting at the seams. We sit in our too-small living rooms, desperately devising ways of expanding our homes. The loft has been done, digging out the cellar will cost a fortune. So, what does the homeowner do next?

It's time to prioritise our own needs over those of our cars. It's time we admitted that we will never use the workbench, that a third of a can of paint does not merit its own room in the house. It's time to reclaim the garage space.

Even the smallest garage can account for at least 60 square feet of floor space. With several specialist conversion companies now enjoying a boom, turning a garage into an office, bedroom, home-cinema den or dining room could be the most cost-effective way to boost the size and value of your home.

That's exactly what Alistair Fleming of Flemings Associates did to a garage in south London. His clients had plenty of bedrooms, but were short of living space downstairs, and saw their redundant garage as the solution. The local planners insisted that they kept the existing façade and doors, but behind that, they now have an integrated room that flows seamlessly into the rest of the house.

The walls and floor were kept consistent with the main house to unite the living room with the new play area, and a sliding door was added to shut the room off when it's not in use. A new, oversized window at the rear of the extension draws in plenty of natural light, providing huge views over the garden. The new room also doubles up as a useful entertaining space. The conversion is a triumph.

But how do these conversions affect the value of your property? Is it something worth carrying out for profit alone, if you're thinking of selling up? Dominic Pasqua, a partner at Knight Frank's Wimbledon office, thinks it can have a "massive" impact on your property's price tag. "If a house has off-street parking and a good-sized garage, a quality conversion could add £100,000 to the value of a house worth £1m. It makes it more desirable and therefore easier to sell."

This is backed up by Anglian Home Improvements, a company that specialises in converting garages. It quotes an average single-garage conversion would cost between £6,000 to £10,000, but claims that the work can increase the value of a property by up to 6 per cent. This means that a three-bedroomed semi-detached house worth £250,000 that has £7,500 spent on converting its garage, could add £15,000 to its asking price.

But converted garages won't increase the value of every house, warns Pasqua. "Areas where private parking is scarce or at a premium may find that garage conversions have no effect on the house's value and could actually take away one of the main attractions to potential buyers."

The interiors expert Elizabeth Wilhide, author of Converted: How to Extend Your Home Up, Down and Out, has some smart ideas and useful tips on turning unused garages into assets. Whether planning permission is required can often be a grey area, and Wilhide offers the following guidelines: "In planning law, garages may be considered as extensions,depending on their size and location. If you are converting a garage and you have not already used up your 'permitted development rights' on other extensions, you probably won't need planning permission, unless you are intending to carry out major changes that would affect the appearance of your home from the street, your home is listed or you live in a conservation area."

Wilhide continues: "Also, if you are intending the conversion to house a new commercial activity, your plans will fall under legislation concerning change of use. Err on the side of caution and investigate the position with your local planning officer first."

Utilising garages can open up a whole range of new possibilities for your home, and create less disruption than you might think. "Attached garages can be absorbed very easily into the rest of your home," suggests Wilhide, "simply by adding a connecting door between the two if one does not already exist. It is also a relatively simple procedure to install windows in place of the existing garage doors. The opening is already made, so you won't be affecting the structure of your home."

Rooflights could provide another option, especially if you're creating a studio or office, but beyond these structural considerations, the work will largely consist of fitting out the interior, adding insulation up to current standards, and extending central heating and other services if these do not already exist.

And don't forget detached garages, which can also be converted as stand-alone extensions. Integrate them more closely with your house by adding a covered walkway that will also protect you from the elements in bad weather. Annexes like these make perfect offices or overspill bedrooms, helping to keep work and relatives from invading your home.

It seems that garages are the new lofts. Rising house prices and families needing extra space have fuelled this mini boom in garage conversions, and the realisation that there has always been an extra, decent-sized room in our home is slowly dawning on thousands of us. All we need to do now is find somewhere else to hoard all that junk.

'Converted: How to Extend Your Home Up, Down and Out' by Elizabeth Wilhide is published by Collins, £20; Fleming Associates: 07976 248475; Anglian Home Improvements, 0800 500 600, www.anglianhome.co.uk