How to Build the Perfect Kitchen Extension


Currently, one of the most sought after features in a modern home and one of the most popular home improvement projects are open plan kitchen extensions.

This is hardly surprising as most households find that the kitchen/dining space is the room they spend the most time in whether it be cooking, eating, socialising, working or relaxing.

The key to creating the perfect open-plan kitchen is getting the space and the layout right first.  Kitchen units, design details and decoration can all be decided upon later.

(Image curtesy of

How much will a kitchen extension cost?

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

Redesigning work is likely to cost £500–800 per m². Converting a garage will cost £950-1,250 per m². A basic extension will cost from £1,050-1,450 per m². A more individual extension with bespoke windows and doors will cost £1,450-1,850. Cellar conversions cost £950-1,150 per m². New basement extensions cost £2,500-4,000 per m².

Before planning your kitchen extension, there are some important questions to ask yourself in order to ensure you achieve exactly 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

Every house will have different viable options when planning to extend.  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.

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 your kitchen extension only requires internal alterations to make more space, such as knocking through between a kitchen and dining room, then these layout plans can be drawn up yourself to scale.  You can then commission an engineer who will be able to prepare drawings and calculations for the structural alterations for submission to the local authority and also for your builder to use.

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 it is advisable to commission an architect to produce the drawings you require.  You will require detailed drawings of the layout, elevations and all the design details showing how the project will comply with Building Regulations.

Getting the design of the space right is fundamental.  By looking at what you specifically need and desire from your new kitchen will help you plan your different areas 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.

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.