There are different reasons for building an extension. You might want to create more space for a new addition to the family. You might want to transform your loft into a study space. You might want to boost the value of your home.Whatever the reason, as with any property project, building an extension requires strategy and planning – not to mention patience.Tony Saffert, Head of Strutt & Parker's Building Surveying department, offers some advice to get you started.

Don’t neglect usable space

When I go out and look at properties where an extension is being considered, I’m often surprised at how much under-utilised space there is.

Extensions can be expensive, so a starting point is to think about how you could change your existing space to fit your needs. You’d be surprised at how even minor alterations can change the look and feel of a house.

The way we use our homes has changed. Think about it: when was the last time you actually used your dining room? These days we often eat in the kitchen or the living room, making your dining room a massive space going virtually unused.

Sliding walls and doors could be fitted in the dining room to optimise the space. Why not expand the size of your kitchen by taking down a wall?

Can you optimise your existing space? If so, you might not even need an extension.

Strategy for extension

If you have exhausted all possibilities and decided to go ahead with a formal extension, start by putting a strategy in place.

This involves sketching out a timeline for the progression of the project and setting a budget. But the most important thing is to make sure you know why you want an extension and how it will benefit your property and, by extension (forgive the pun), your life.

Some extensions can only serve to damage a property – just adding space can be a bad thing to do. Your extension needs to be valuable. You don’t want to end up with a dark hole with no source of natural light coming in.

Think cleverly about how you can extend – the best ones don’t feel like extensions at all. Look at the orientation of your property – where is the sun path? If you are trying to create a large kitchen space for dining, food and family gatherings, you want sunlight and access to the garden.

Planning permission

Changes to planning law in 2008 mean many more extension projects do not fall under the gaze of regulation. But you will still need to check whether you need planning permission.

Under permitted development rights you are allowed to extend and make some changes to a property without securing consent, assuming you meet certain criteria. Note though that listed buildings and properties in conservation areas do not fall under these rights.

If you do need planning consent, check with your local authority for the specifics as each one has different rules and regulations. Typically though, a 40% maximum increase in space is the usual cap.

You will also need to apply for building regulation consent – importantly, this is separate from planning permission so don’t assume if you secure permission you can go ahead with your extension.

Building regulations approval is usually needed if you put up a new building, extend or alter an existing building or install fittings in a building, such as replacement windows.

Potential for disputes

Any disputes – such as protests from your neighbours – would usually be sorted out via the planning process, should this take place.

Typical concerns include windows that overlook a neighbouring property and blocking sunlight. As a result, balconies are often difficult to secure permission for and if you live in a terrace, it is impossible to extend without taking light.

As long as you comply with planning rules and building regulation, it is unlikely any disputes would arise. But as a good neighbour, it would still make sense to approach your neighbours before you apply for planning permission to let them know about the project. This all helps to secure approval.

Long-term value

My colleague, Edward Church, Head of Estate Agency in Kent, has marketed many homes with extensions over the years and gives his view on the value extensions can add to your home: "Building an extension can significantly enhance the value of your home. This is most obvious when in town, where space is always at a premium. However, be cautious about the negative impact of the loss of some outside space which might outweigh the benefits."

"On an older house, the value of the extension might not be added to your home overnight, as the costs can be more substantial as work becomes intricate. Therefore, do not always expect an immediate uplift in value."

"Homeowners often ask if it is best to extend their home before selling, but this is not always a good idea. Investing substantial sums is best done when you will have time to enjoy the new works yourself, and to derive benefits beyond the financial gain that might be achieved. The buyer might not need what you build and will therefore not want to pay for it." says Ed.