Chelsea, Greater London
Two-storey rear extension in Chelsea
A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. If you live in Chelsea and want to know what a two-storey rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Chelsea sits in Greater London, with postcode districts including SW3, SW7 and SW10. In Chelsea, a two-storey rear extension is worth comparing with the cost of moving once stamp duty, agents' and legal fees are counted.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a two-storey rear extension cost in Chelsea?
For Chelsea we work from the London rate: £2,340–£3,510 per square metre of new floor, including VAT, standard specification. London prices sit at the top of our range because of labour rates, access through the house, parking suspensions and skip licences.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £70,000–£105,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £112,500–£168,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a two-storey rear extension in Chelsea?
Here is how the rules in England apply to a two-storey rear extension in Chelsea.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Chelsea like to extend?
Much of Chelsea is Victorian and Edwardian terraced housing with narrow back additions, which suits side returns, wraparounds and 3 metre rear extensions. Many streets are in conservation areas, gardens are short, and almost everything comes through the house or along a rear alley.
How a two-storey rear extension in Chelsea comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Two-storey rear extensions near Chelsea
From Chelsea, the nearest places we also cover are Battersea (1.1 miles) and Fulham (1.4 miles).
- Two-storey rear extension in Battersea
- Two-storey rear extension in Fulham
- Two-storey rear extension in Pimlico
- Two-storey rear extension in Notting Hill
- Two-storey rear extension in Shepherds Bush
Other work in Chelsea:
FAQ
Two-storey rear extension questions in Chelsea
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Do I need planning permission for a rear extension in Chelsea?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
What is the 45-degree rule?
Many councils check that a two-storey extension does not cross a 45-degree line drawn from the nearest habitable window of the neighbouring house. We test it at the first drawing.
What postcode areas do you cover around Chelsea?
Including SW3, SW7 and SW10, and the surrounding Greater London area.
How much does a two-storey rear extension cost in Chelsea?
As a guide, £2,340–£3,510 per square metre including VAT for a standard specification. For example, 3 m × 5 m footprint, two floors (30 m²): about £70,000–£105,500 at that rate. Your written price follows the survey.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.