Covering Chelsea
Alongside Chelsea, we also cover Battersea, Fulham (1 miles to the west) and Notting Hill.
Homes in London
Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.
What do you get with an upward extension?
The first question is whether the existing walls and foundations can carry the extra load, so we start with a structural survey. Then we design either a full first floor or a raised roof with dormers, handle planning or prior approval, and build the new storey while protecting the floor below.
- Design and planning or prior approval application
- Roof removal and temporary weather protection
- New first-floor structure, walls and roof
What will an upward extension cost?
Typical ranges for bungalow and upward extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Bungalow and upward extensions | Guide price incl. VAT |
|---|---|
| Chalet conversion with dormers (total) | £45,000 to £85,000 |
| New first floor, standard specification | £2,200 to £2,800 per m² |
| New first floor, good specification | £2,800 to £3,300 per m² |
| New first floor, high specification | £3,300 to £3,800 per m² |
Do you need permission for an upward extension in Chelsea?
English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.
In England, Class AA permitted development allows an extra storey on many detached and semi-detached houses built between July 1948 and October 2018, subject to a prior approval application covering design, neighbours’ amenity and other matters.
What should I think about before starting?
- Some bungalow foundations need strengthening before a storey can be added.
- The staircase takes space from the ground floor plan.
From first call to completion
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Bungalow and upward extensions: common questions
How much does it cost to add a storey?
Around £2,200 to £3,800 per square metre of new floor including VAT, or £45,000 to £85,000 for a chalet conversion with dormers.
Is an upward extension permitted development?
In England, Class AA allows it on many post-1948 houses through a prior approval application. Elsewhere planning permission is needed.
Do you work in Chelsea?
Yes. Chelsea is within our coverage for bungalow and upward extensions, along with nearby Battersea and Fulham.
Bungalow and upward extensions in nearby towns
- Bungalow and upward extensions in Battersea
- Bungalow and upward extensions in Fulham
- Bungalow and upward extensions in Notting Hill
- Bungalow and upward extensions in Shepherd's Bush
Learn more about bungalow and upward extensions, or see every project we cover in Chelsea.

