Not only can an extension improve your enjoyment of your home and make the space more compatible with your lifestyle, but it can add serious value to your property. So what are the ways you can improve and extend your home? Are there particular kinds of extensions that work better than others? And what research should you do before you embark on a project? We asked the experts for their advice

What you need to know before beginning an extension

Know what you want, advises Chris Eaton, Associate Director at leading London architectural practice, Stiff & Trevillion: ‘Why are you extending and what do you want the extension for?’ he asks. ‘Is it about daylight, space or storage?’

‘You can just extend and fill a space, but the end result won’t be as good if you haven’t thought about how it is going to be used,’ agrees Brendan Day, Head of Design at Apropos, the contemporary conservatory and extension specialists. Chris also suggests you do a mood board or use a Pinterest page to gather together images of extensions and styles that you like to show your architect or contractor – it will give them a useful starting point.

Don’t embark on a huge extension project without first really looking at how your existing space is used, advises Chris. ‘Is your property being used efficiently? Often there are corridors, or even rooms, that are underused and re-organising your space is cheaper than extending.’

‘An architect can suggest alternatives that the client hadn’t already considered,’ Chris says.  Brendan thinks you need a good builder. ‘Quite a lot can be done to most properties under Permitted Development – that is without a full planning application; work with a specialist who knows what’s possible. It’s not always a requirement to have an architect, but for some projects it is essential.’


Stiff & Trevillion’s extension uses an internal glass wall to light the stairwell

Budget-wise, a loft extension will generally cost less than a ground floor extension, which in turn costs less than a basement excavation. ‘For most people the creation of more living space is the main criteria, and this is usually best achieved with a ground floor rear or side extension,’ says Brendan. ‘This kind of extension is usually simpler, takes less time, and creates a nicer living environment.’

As to the current London obsession with basement conversions: ‘A basement can add a lot of space, but it is a substantial project and requires a substantial financial investment,’ says Brendan. The benefits of basement conversions, says Chris, is that they have ‘a relationship with the existing living spaces of the house and can add play spaces, kitchens or dens.’

There’s plenty of debate about whether, with an extension, you should emulate the existing style of your property or whether it’s better to make any additions markedly modern. Chris is in the latter camp: ‘We would advise against creating a pastiche of the existing property. However, what is proposed should be driven by what the clients are hoping to gain from the extension – it wouldn’t be appropriate to construct a glass cinema room for example.’ Brendan agrees: ‘Properties have always been developed through the ages and unless particular planning restrictions need to be met, then I think it’s generally better to go with what is current. For most people the extension should reflect their lifestyle rather than the host building.’

Victoria Geoghegan, Head of Development Management and Building Control at Islington Council, introduces you to the planning process

Permitted development rights: these allow you to make certain types of minor changes to your house without having to apply for planning permission. These only apply to houses and not flats, maisonettes or other buildings. Porches, single-storey rear extensions, dormer windows, fences and some outbuildings are all examples of what is covered by permitted development. Certain parts of a borough, such as conservation areas or areas covered by Article 4 Directions, will have more restrictive permitted developments. Listed building consent is also required if the property is listed.


Apropos Jobson’s ppen plan London extension brings the outside in

Planning permission: this is required for most development, including significant extensions and alterations to buildings, new builds, changes of use and conversions. Most councils operate an advice service and you should always check before embarking on any works. With all building work, the owner of the property (or land) is ultimately responsible for complying with the relevant planning rules and building regulations.


Marston & Langinger is known for its conservatory extensions

When applying for planning permission, it is advisable to discuss your proposal with the council – this is called pre-application discussions. When first submitted, most applications are invalid because they do not include the correct information – whether that’s missing drawings or the planning fee – so do refer to the validation check list on your council’s website, and use a reputable architect or plan drawer.

Building regulations: these are required for most construction projects. The process includes pre-site approval (full plans, building notices) and on-site approval during construction. Your local authority will offer this service and has a wealth of local knowledge and experience.

Most Read