An extension is a great way to make your home bigger and better, – as long as you don’t make your garden too small in the process.

While building an extension won’t be cheap and will take some time, it’s often better than having to move home when your family has outgrown its current one.

Depending on your home’s layout and as long as the new layout complies with building regulations, a ground-floor extension can be turned into pretty much anything, typically a kitchen-diner, especially in a side return, but also an extra living area or den, a home office or even a bedroom and en suite, perfect as a granny or nanny annex.

If you can run to a two-storey extension, you’ll increase both your living and sleeping space, or can add a dressing room or extra bathroom upstairs – whatever you need.

The problem with two-storey extensions is that they often require planning permission, whereas ground-floor extensions can often be done under your home’s permitted development rights, providing it has them – flats and maisonettes don’t and some houses have had theirs removed.

If your home doesn’t have these rights or you want to build an extension that can’t be done under permitted development, you’ll have to go through the planning process – which can be lengthy, expensive and frustrating.

The Government is changing the permitted development rules for three years (until May 30, 2016) so that terraced and semi-detached houses can extend to the rear by six meters (on the ground floor) without planning, or a whopping eight metres for detached houses. This is double the usual size and so faced opposition in Parliament.

The agreed compromise is that the local council will have to be notified of a planned extension and then adjoining neighbours will be given the chance to object.

To be done under permitted development, the extension must conform to the rules regarding width, height and materials, etc – see www.planningportal.gov.uk.

For example, extensions (and other buildings) mustn’t account for more than 50 per cent of the land around the original house, and the width of a side extension mustn’t be more than half the width of the original house.

There are different rules for single and two-storey extensions and for rear and side ones (side extensions on ‘designated land’, which includes conservation areas, are not permitted development), so it can be quite complicated.

With listed buildings, you’ll need listed building consent from the local council for any sort of extension. You should also check the terms of the lease if your home’s leasehold, as you’ll probably need the freeholder’s permission to build an extension.

Any proposed extension along or close to a shared boundary with a neighbour falls under the Party Wall Act, meaning you’ll need a party wall agreement with the neighbour, which can be an expensive and frustrating process if there’s a dispute.

While you can get flat-pack extensions, just as you can get flat-pack homes, most extensions are built in a more conventional way, with an architect designing it and a builder constructing it.

If the architect also manages the project and contractors (usually charging a percentage of the build cost), you should have less to do and worry about.

You may prefer to manage the build yourself, or the builder may be prepared to do it, but someone will need to take responsibility for getting everything and everyone in the right place at the right time.

As well as time to build the shell of the extension, you’ll need to factor in fitting-out time.

A kitchen will take longer than other rooms and will also, of course, be more expensive.

Like any other big home-improvement project, an extension can easily go over budget, so keep a careful eye on the numbers and schedule. And it is vital to have a contingency fund for unexpected problems.

HOW-TO TIP If you have a patio, spruce it up with this how-to tip from celebrity builder Tommy Walsh.

Sweep the patio with a stiff-bristled brush to remove any leaves, dirt and debris, then dilute Jeyes Fluid (£10.98 for 1ltr, B&Q), following the instructions on the tin.

Apply the solution to the patio and leave for 30 minutes before rinsing thoroughly. Importantly, don’t forget to do a test spot first.