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 Sidcup?
In Sidcup, a kitchen extension typically costs £2,900–£4,400 per m² including a mid-range kitchen, including VAT at 20% (standard rate). For a typical 22 m² project that is roughly £64,000–£97,000. That range is adjusted for London, where domestic building work typically costs around 30% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (15 m²) | £43,500–£66,000 |
| Typical project (22 m²) | £64,000–£97,000 |
| Larger project (31 m²) | £90,000–£136,500 |
| Rate per m² | £2,900–£4,400 |
What moves the price most:
- Kitchen units, worktops and appliances
- Glazing and roof lanterns
- Underfloor heating and flooring
- Who supplies the kitchen
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a kitchen extension in Sidcup?
Whether you need planning permission depends on your house and its location 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.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
The work we manage on a kitchen extension:
- Extraction ducted to outside
- Flooring and decoration
- Electrics, lighting plan and sockets
- Kitchen layout planned alongside the extension design
- Extension structure, roof and glazing
- Building control sign-off
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 Sidcup
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
From DA14 outwards, we take on projects throughout Sidcup and the surrounding parts of Greater London.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about kitchen extensions in Sidcup
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.
How long does a kitchen extension take in Sidcup?
Typically 11 to 16 weeks on site, including kitchen fitting. Design and approvals beforehand usually take 6 to 12 weeks.
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.
How much does a kitchen extension cost in Sidcup?
In Sidcup, a kitchen extension typically costs £2,900–£4,400 per m² including a mid-range kitchen, including VAT at 20% (standard rate). A typical 22 m² project comes to roughly £64,000–£97,000. Your fixed price depends on the survey and drawings.
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.
