Extending your home in Chelsea
We design and build house extensions for homes in Chelsea and the surrounding Greater London area, with guide prices adjusted for the region.
- Postcode districtsSW1W, SW1X, SW3, SW5, SW7, SW10
- Price regionLondon (×1.3)
- Planning rulesEngland
- Site visitFree, no obligation
Popular extension prices in Chelsea
Use these Chelsea guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Double-storey extensions | 32 m² | £74,500 – £98,000 |
| Extensions over a garage | 12 m² | £32,500 – £42,500 |
| Kitchen extensions | 20 m² | £54,500 – £69,000 |
| Conservatory replacement extensions | 14 m² | £39,000 – £50,500 |
| Orangery extensions | 16 m² | £58,000 – £73,000 |
Where we work near Chelsea
Across SW1W, SW1X, SW3, SW5, SW7, SW10, we can visit, measure and advise. The same team covers Battersea (1 mile), Fulham (1 mile), Notting Hill (2 miles), Shepherds Bush (3 miles), Putney (3 miles), all within easy reach. Just over the Surrey border, East Molesey is about 10 miles away.
Planning and building control in Chelsea
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Choosing the right extension in Chelsea
Across London, terraced houses with narrow side returns and tight access are the norm, which shapes everything from party wall notices to how materials reach the back garden.
For many houses here, wraparound extensions, side return extensions or kitchen extensions gives the most useful space for the budget.
Choose an extension type
- Timber frame extensions · from £27,000
- Kitchen extensions · from £35,000
- Pitched roof extensions · from £28,500
- Glass box extensions · from £39,000
- Orangery extensions · from £39,000
- Conservatory replacement extensions · from £26,000
- Building regulations for extensions · from £1,150
- Bedroom extensions · from £33,500
- Annexe extensions · from £71,500
- Porch extensions · from £5,200
- Double-storey extensions · from £49,000
- Flat roof extensions · from £27,000
- Planning permission for extensions · from £450
- Extensions over a garage · from £31,000
- Wraparound extensions · from £46,500
- Home office extensions · from £20,500
- Extension plans and drawings · from £1,550
- Bungalow extensions · from £34,000
- Utility and boot room extensions · from £18,000
- Single-storey rear extensions · from £27,000
- Side return extensions · from £23,000
- Side extensions · from £28,500
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions about extensions in Chelsea
How much does an extension cost in Chelsea?
Using our London factor (×1.3), a standard-spec single-storey extension of 20 m² is a guide £53,000 to £68,000 including VAT, and a 32 m² two-storey extension £74,500 to £98,000. Your written price follows the survey.
Will my neighbours need to be told?
If you apply for planning or prior approval the council notifies them, and in England party wall notices may be needed for work near a shared boundary.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
How long does an extension take in Chelsea?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Book a free site visit in Chelsea
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.