How to build the perfect kitchen extension

Find out how to create the perfect kitchen extension, from using and designing the space to the overall costs

TODO alt text

If you’ve set your heart on creating a large open-plan kitchen extension then you are not alone. This is one of the most sought-after features in a modern home and one of the most popular home improvement projects.

Most households find the kitchen/dining space is the heart of family life and the room they spend most of their time in — cooking, eating, socialising, working and relaxing. The key to creating the perfect open-plan kitchen is getting the space and the layout right first before deciding on kitchen units, design details and decoration later.


Related articles:  The ultimate guide to extending your home | 10 ways to cut the cost of your extension | 12 kitchen extension ideas all under 100K

How much will a kitchen extension cost?

Prices will vary depending on the work you carry out, but as a guide:

  • Redesigning work is likely to cost £500–900 per m².
  • Converting a garage will cost £1,000–1,250 per m².
  • A basic extension will cost from £1,500–1,900 per m².
  • A more individual extension with bespoke windows and doors will cost £1,900–2,200.
  • Cellar conversions cost £1,150–1,850 per m².
  • New basement extensions cost £3,000–5,000 per m².

Find out how much your kitchen extension will cost with our FREE extension cost calculator

How will to use a kitchen extension?

The amount of space you need for your kitchen will depend on how you plan to use it. Ask yourself these questions to help you clarify what you need:

  • Will your kitchen be solely for preparing meals, or do you want dining space too?
  • Do you want to be visible when cooking, or tucked around a corner?
  • Will you entertain in the kitchen, or only have informal dining there?
  • Do you want some living space open to the kitchen?
  • Do you need a separate utility room, larder or store?

Finding space for a kitchen extension

If you want access to the garden and privacy, the kitchen is most likely to be at the rear or side of the house. If possible, it should be accessible from the main hallway and not through another room.

You may be able to achieve the space you need by remodelling the existing layout, removing some internal walls to link two rooms together, or by converting and linking an integral garage.

kitchen extension with a feature mural

Alternatively, you could extend at the rear or side of your home to gain extra space. In a townhouse it may make sense to convert and/or extend the cellar to form a basement storey, with a lightwell leading up to the garden.

Small extensions to a house may not need planning permission if they fall within the definition of permitted development. Larger extensions, or additions to a flat, always need planning permission. Alterations to a listed building always require listed building consent, whether or not the work is permitted development.

How to design a kitchen extension

If you are planning on redesigning your home and making only internal alterations to create more space — for example, knocking through between a kitchen and dining room, you could draw up the layout plans yourself to scale, then commission an engineer (visit for details). They will be able to prepare drawings and calculations for the structural alterations for submission to the local authority and to pass on to your builder.

No planning permission or other drawings will be required. However, if your property is leasehold, you will need to obtain permission from the freeholder.

If you plan to extend to add more space, then you will need drawings of the layout, elevations and all the design details, showing how the project will comply with the Building Regulations. It’s best to leave the drawing of these to an architectural designer — either an architect (visit or an architectural technical designer (

architecturally designed kitchen extension

Getting the design of the space right is fundamental. This will help to ensure the kitchen is in the right location in the house and that it has good access from the central hallway and on to the garden or patio. It will help you make the most of light, plan your different zones for cooking, dining and living, plus decide where to position utility space and appropriate lighting.

Once you have the space that you want designed, you can start thinking about the kitchen layout. It is worth consulting two or three experienced kitchen designers for their ideas. Make sure you give them a clear brief of what you are trying to achieve, but listen to their advice in terms of layout to suit the space, such as designing a galley, L-shaped or U-shaped layout, or introducing an island or appliance wall.

A good designer will understand the importance of function (ergonomics) and incorporate all the appliances you have specified. Once the basic layout is agreed, you can finalise details like the style of the units, cupboard doors and drawer fronts, worktops, splashbacks, sink, taps and the rest of the design details.

For inspiration for your kitchen extension, CLICK HERE and see our selection of contemporary kitchen ideas

When you have finalised your layout and chosen your supplier, the designer will be able to produce detailed wiring and plumbing plans so the builders can put the services in place during the building phase. You can then have the plastering and decorating work done and the flooring laid, ready for the kitchen installers to arrive.