How to plan and design an extension

Forget moving – make the most of what you have by extending your house up, out or down...

Preparing a brief

‘Design is not the same as art,’ says Mark Dyson of Enclosure Architects. ‘An architect is, in fact, a problem solver, not an artist. Consider what you want from your extension and how it will make your life better.’ Sit down with your architect and identify what you want to achieve. Don’t overdo the brief, but make sure it’s unambiguous and well-defined.


  • Consider how the finished project will function. Do you need an extra bedroom, crave a bigger kitchen or want more light in your home? Who will use it, and for what?
  • Think about the design direction. ‘Have you already seen something you like the look of?’ asks architect Guy Morgan-Harris. ‘Do you want it to contrast or be in keeping with the existing structure? It’s really handy to collect images of projects that appeal to you.’
  • Consider internal finishes such as flooring, lighting, storage and even smaller things like light switches in the early stages, as they’ll all affect your budget.
  • Agree on a timescale. ‘If you rush a job you may lose out on quality, and the project may end up costing more as there will be less time to source materials,’ says Guy.

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