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.
How much does a kitchen extension cost in Cornwall?
In Cornwall, a kitchen extension typically costs £2,300–£3,450 per m² including a mid-range kitchen, including VAT at 20% (standard rate). For a typical 22 m² project that is roughly £50,500–£76,000. Building costs in the South West are close to the UK average, so the figures for Cornwall are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (15 m²) | £34,500–£52,000 |
| Typical project (22 m²) | £50,500–£76,000 |
| Larger project (31 m²) | £71,500–£107,000 |
| Rate per m² | £2,300–£3,450 |
Your quote will depend mainly on:
- Underfloor heating and flooring
- Extension size and roof design
- Who supplies the kitchen
- Island with sink or hob, which needs services in the floor
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a kitchen extension in Cornwall?
The approval route for Cornwall is set by planning law in 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most kitchen extensions:
- Building control sign-off
- Kitchen layout planned alongside the extension design
- Extraction ducted to outside
- Extension structure, roof and glazing
- Kitchen fitting, worktops and splashbacks
- Flooring and decoration
How long does it take?
Allow 11 to 16 weeks on site, including kitchen fitting. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Cornwall
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Towns we cover in Cornwall include Redruth, Falmouth, St Austell, Truro, Camborne and Newquay.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about kitchen extensions in Cornwall
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.
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.
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.
How much does a kitchen extension cost in Cornwall?
In Cornwall, a kitchen extension typically costs £2,300–£3,450 per m² including a mid-range kitchen, including VAT at 20% (standard rate). A typical 22 m² project comes to roughly £50,500–£76,000. Your fixed price depends on the survey and drawings.
Do you build kitchen extensions in Cornwall?
Yes. We build kitchen extensions across Cornwall, including postcodes EX22, EX23, PL10, PL11 and PL12. Every project starts with a free home visit.
