What is a wraparound extension?
A wraparound extension combines a side return and a rear extension into one L-shaped addition. It gives the largest possible ground floor, often creating an open-plan kitchen, dining and living space across the whole width of the house.
How much does a wraparound extension cost in Chelsea?
In Chelsea, a wraparound extension typically costs £2,850–£4,150 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £80,000–£116,000. 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 (20 m²) | £57,000–£83,000 |
| Typical project (28 m²) | £80,000–£116,000 |
| Larger project (39 m²) | £111,000–£162,000 |
| Rate per m² | £2,850–£4,150 |
The biggest cost drivers are:
- Access for materials on terraced streets
- Steelwork and propping of the existing house
- Total footprint and the amount of glazing
- Party wall surveyor fees for one or both neighbours
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a wraparound extension in Chelsea?
Before anything is built in Chelsea, we confirm which approvals apply in England. In England a wraparound extension combines side and rear elements, which normally takes it outside permitted development, so a householder planning application is made.
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most wraparound extensions:
- Walls, roof and glazing
- Building control completion
- Underfloor heating option, electrics and plastering
- Design and planning application
- Removal of internal and external walls
- Foundations and drainage
How long does it take?
Build time is typically 12 to 18 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Chelsea
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
Projects in Chelsea (SW3 and SW10) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about wraparound extensions in Chelsea
Can we keep a separate living room?
Yes. Many clients keep the front room separate and open up only the back of the house.
Who approves a wraparound extension in Chelsea?
Planning matters in Chelsea go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
What about the old back addition?
The side wall of the back addition is usually removed and replaced with a steel beam, so the old kitchen joins the new space.
How much does a wraparound extension cost in Chelsea?
In Chelsea, a wraparound extension typically costs £2,850–£4,150 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £80,000–£116,000. Your fixed price depends on the survey and drawings.
Will both neighbours be affected?
Usually only the neighbour on the side return side, but rear foundations near either boundary can trigger party wall notices.