How to plan and design an extension

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

Ground-level extensions

Up until quite recently, the front of the house was the most social area of the home and the kitchen and rear were purely functional spaces. Now, with cooking the nation’s favourite pastime, open-plan kitchen-diners are increasingly in demand. ‘Buyers like spaces that suit their lifestyle and aspirations, and side extensions and large living/dining areas appeal to the way people live now,’ says Michael O’Flynn. ‘Having a large, well-lit family space that has access to the garden is a big selling point.’


The latest ground-level extensions are seamlessly integrated inside, but also blur the boundaries between inside and out. ‘The flow of the structure, finishes and materials such as the flooring can work with the outside space to make them feel like the same entity,’ says Mark Dyson. ‘Full-height doors can help to connect the interior to the garden, and even in the winter when the doors are closed it can still give the impression it’s one large space.’


  • Providing your property hasn’t been extended in the past, you can extend by up to 50 cubic metres, as long as it’s not more than 4m above ground level, or 10 per cent of the existing floor space, without obtaining planning permission. Even so, always check before embarking on a project in case there are other conditions that apply.
  • Sometimes simply removing internal walls can open up a space without having to eat into valuable footage in the garden. And don’t forget that making use of a side return can increase the size of your kitchen by up to 40 per cent.
  • Part L Regulations, which relate to a building’s thermal efficiency, mean there is now a restriction on how much glass you can use, but this can be offset by installing high- efficiency insulation and by using Low E (low emission) double or triple glazed panels.

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