What is a kitchen extension?
A kitchen extension is an extension designed around a new kitchen, usually an open-plan kitchen, dining and family space at the back of the house. We build the extension and fit the kitchen as one project, so plumbing, electrics and lighting are planned around the layout from the start.
Planning the kitchen before the walls go up avoids moving drains and sockets later. It also lets us place roof lanterns and windows where they light the worktops and table.
What we handle
- Kitchen layout planned alongside the extension design
- Extension structure, roof and glazing
- Drainage and water supply positioned for the sink and appliances
- Extraction ducted to outside
- Electrics, lighting plan and sockets
- Kitchen fitting, worktops and splashbacks
- Flooring and decoration
- Building control sign-off
Options to consider
Island layout
An island gives seating and prep space but needs at least a metre of clearance all round.
Utility room
A separate utility keeps laundry out of the kitchen; it can sit in the old back room.
Roof lantern over the table
A lantern above the dining area brings daylight into the middle of a deep room.
Supply your own kitchen
You can buy the kitchen yourself and we fit it, or we can supply it.
How much does a kitchen extension cost?
A kitchen extension typically costs £2,250–£3,400 per m² including a mid-range kitchen across the UK, including VAT at 20% (standard rate). A typical 22 m² project comes to roughly £49,500–£75,000. Build time is usually 11 to 16 weeks on site, including kitchen fitting. Design, structural calculations and council fees are extra.
| Region | Guide range (per m² including a mid-range kitchen) |
|---|---|
| London | £2,900–£4,400 |
| South East | £2,500–£3,800 |
| East of England | £2,400–£3,600 |
| South West | £2,300–£3,450 |
| West Midlands | £2,200–£3,300 |
| East Midlands | £2,150–£3,250 |
| North West | £2,100–£3,200 |
| Yorkshire and the Humber | £2,100–£3,150 |
| North East | £2,000–£3,050 |
| Wales | £2,050–£3,150 |
| Scotland | £2,200–£3,300 |
| Northern Ireland | £1,950–£2,900 |
What changes the price:
- Extension size and roof design
- Kitchen units, worktops and appliances
- Island with sink or hob, which needs services in the floor
- Underfloor heating and flooring
- Glazing and roof lanterns
- Who supplies the kitchen
Use the guide price tool for a figure based on your measurements, or see all guide prices.
Do I need planning permission?
England
In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Wales
In Wales a single-storey rear extension is often permitted development: up to 4 metres beyond the rear wall and up to 4 metres high, with eaves no higher than 3 metres within 2 metres of a boundary and no more than half the land around the original house covered. Wales has no larger home extension prior approval route, so deeper extensions need a planning application, as do extensions to flats, listed buildings and houses whose rights have been removed.
Scotland
In Scotland a single-storey extension is often permitted development (Class 1A): where any part is within 1 metre of a boundary, it can project up to 3 metres from the rear wall of a terraced house or 4 metres on other houses, with eaves no higher than 3 metres, an overall height of 4 metres and no more than half the front or rear garden covered. The rights do not apply in conservation areas or to flats, and a building warrant will usually still be needed before work starts.
Northern Ireland
In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows single-storey rear extensions of up to 3 metres on attached houses and 4 metres on detached houses, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Houses with removed rights need planning permission, listed buildings need consent, and in conservation areas extensions must stay single-storey and must not come forward of the front or side walls.
Even when planning permission is not needed, building regulations approval (a building warrant in Scotland) usually is. We make the applications and book the inspections.
How long does it take?
Typically 11 to 16 weeks on site, including kitchen fitting. Surveys, design and approvals usually take 6 to 12 weeks beforehand.
How it works
- 01
Free visit
We look at the property, discuss what you want and measure up.
- 02
Design and fixed quote
Drawings, calculations and an itemised price for the agreed specification.
- 03
Approvals
Planning or permitted development, building regulations and neighbour matters.
- 04
Build and sign-off
Built to a written programme, with a completion certificate at the end.
Kitchen extensions: questions and answers
Should the kitchen be designed before the extension?
Yes. Knowing where the sink, hob and island will go lets us place drains, ducting, sockets and windows correctly during the build.
Can I buy my own kitchen?
Yes. You can supply it and we fit it, or we supply it as part of the price. Either way we coordinate deliveries with the build programme.
Will I need planning permission?
The same rules apply as for any extension. Many single-storey kitchen extensions are permitted development; larger or wraparound designs need an application.
How long will I be without a kitchen?
Usually 3 to 6 weeks at the end of the job, once the back wall is opened and the new kitchen goes in. We can help set up a temporary kitchen.
Do I need extraction to outside?
Building regulations require kitchen extract ventilation. Ducting to an outside wall is the most effective option and is planned during the build.
Is underfloor heating worth it?
In a large open-plan space it frees wall space for units and glazing and gives even heat. It is easiest to fit during the build.