How to update a kitchen extension

How to improve the design of a failing extension, including an inspiring case study

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Use this useful guide to give a new lease of life to a dated extension

While adding to the floor area, many old extensions don’t maximise their potential, and fail to meet modern glazing and insulation standards. We look at how to solve the problems of a poorly designed extension

Building work

You may be able to update what you have or you might need to start afresh with a new structure. The size and build quality of the existing extension will influence your choice.

‘If the footprint of the extension stays the same, you can keep what you have in some instances,’ says Federica Vasetti, partner at architectural firm Dittrich Hudson Vasetti, ‘but if you are trying to make it bigger, there’s no point in linking new walls and existing walls.’

To update it, your current extension must have adequate foundations, and you’ll need to be able to insulate it to modern standards cost-effectively.

Possible updates

‘You would usually have to insulate an existing extension internally,’ says Federica. Possibilities for this include the roof, floor and cavity walls.

  • Insulation on the inside of the walls would reduce the internal dimensions of the extension.
  • External insulation is also possible, but would alter the structure’s appearance.

If your extension looks dated, you may be able to change the roof covering or its shape and pitch, go for new doors or windows, or use external finishes such as timber cladding or render for a more attractive design.

Layout and appearance

The major difference between the extensions added to homes in the past and the latest designs is how they work with the rest of the layout.

‘In the 1980s, an extension was seen as an extra room,’ says Federica. ‘More recent extensions are often fully integrated with the back of the house to create a large, open-plan room facing the garden.’

Many modern extensions also have flat roofs, rather than the once typical mono pitch. This allows for good internal height and tall windows to bring in more light.

Tastes have changed when it comes to the external appearance, too. ‘Homeowners no longer necessarily want the extension to look as if it were already there,’ Federica explains. ‘On a period property, a design distinct from the original is a real statement. We may take clues from a house’s style, but reinterpret it in a contemporary key.’

Modern options

Patio doors don’t really feature in contemporary extensions, with sliding or bi-fold designs preferred. Where an open-plan space is created, underfloor heating is a practical, flexible solution.

Where to start

Think about what you need from your extension, and how you will use the space, before calling in an architectural designer. Be open to ideas — a design professional can offer alternatives and show you how to make the most of what you have.

‘Sometimes the space needed is in the existing extension,’ says Federica. ‘People don’t see that they can take down walls to achieve their plans.’

Case study

Dawn and Phill Rushen’s extension to their semi-detached Bristol home is now a light-filled, low-maintenance home office


dated blue kitchen extension


clad kitchen extension

When Dawn and Phill moved into their Victorian home, the building’s original outhouse had been adapted into a workshop accessed via the garden, together with another room linked to the house, with a glazed roof.

‘It was cold in winter, hot in summer, and had no insulation or heating,’ recalls Dawn. ‘It was quite narrow and impractical, with rotten timber, cracking in the walls, and penetrating and rising damp.’

The couple called in architects Dittrich Hudson Vasetti and it was decided to rebuild the structure, with new foundations, and new walls in place of the postwar single-skin brick, which didn’t meet modern standards. The project also provided the chance to knock through into the workshop.

The extension is modern in style as the couple didn’t think trying to blend in with the house would work. Its position also influenced the appearance. ‘We were thinking more of how it would sit with the garden than with the house,’ says Dawn. So as not to encroach on the bay window, a narrow section forms a utility between the kitchen-diner in the house and the wider home office.

Planning permission didn’t present any problems, and Dawn is delighted with her new space. ‘The light is much better, it has heating, and there are blinds to keep out the sun and heat in the summer.’

How much did it cost?

To demolish and rebuild the extension, including fitting the utility room, materials, construction and fees, cost around £42,000.