House extensions in Chelsea.
Chelsea · SW3 · Chelsea basement and extensionCompleted work, photograph
Kitchen and rear extensions for Chelsea terraces and townhouses. Drawn to what the borough allows, then built by the same team.
What a Chelsea house can add.
- CD13
- The borough’s tests for an extension
- £160k to £250k
- A rear kitchen extension, cost guide total
- SW3 · SW10
- Terraces, townhouses and studio houses
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle house and kitchen extensions in Chelsea SW3, under one contract. A rear kitchen extension typically runs £160k to £250k. A side return extension typically runs £140k to £220k. Call 020 7731 6841, and a budget estimate typically follows within seven days.
Chelsea is terraces and townhouses, most of them in conservation areas. Back gardens are often narrow.
The usual move is a kitchen extension at the back, at garden level.
Kensington and Chelsea tests every extension against Policy CD13 of its 2024 Local Plan.
It must sit below the main eaves. It must keep the terrace’s rhythm of rear additions.
We completed a Chelsea house with a kitchen extension and a new basement. One team built both.
What the council allows in Chelsea.
- Council
- Royal Borough of Kensington and Chelsea, Local Plan of July 2024.
- How far back
- No further than the general rear line of the neighbouring extensions. Policy CD13.
- How high
- Not above nearby extensions, and never up to the original eaves or parapet.
- Design
- Windows, materials and finishes must suit the house. A roof level conservatory is resisted.
- Conservation areas
- About three quarters of the borough is conservation area. Applications there must be made in full.
Source: Kensington and Chelsea’s Local Plan 2024, Policies CD4, CD5, CD11 and CD13. Read on 3 October 2026. Policies change, so we read them again for your address.
Built in Chelsea.
Chelsea·Townhouse
Chelsea basement and extension
Our Chelsea kitchen extension, built with a new basement under one contract.
See the project
Chelsea·Townhouse
Chelsea townhouse, opened up and fitted out
A Chelsea townhouse of 4,500 sq ft, opened up under a long rooflight.
See the projectCompleted work, photographs
What a house extension costs in Chelsea.
£160k to £250kA rear kitchen extension. A project total, from our 2026 cost guide.
£200k to £320kA wraparound extension. A project total, from our 2026 cost guide.
A Chelsea extension often waits on a conservation or listed consent first.
The guide figures are project totals.
Fees, party wall costs, contingency and VAT sit outside both.
What Chelsea owners ask about extensions.
In Chelsea
- Every service in Chelsea
- Basement construction in Chelsea
- Interior design in Chelsea
- Luxury refurbishment in Chelsea
- Bespoke joinery in Chelsea
- Party wall surveying in Chelsea
- Loft conversion in Chelsea
- Architectural design in Chelsea
- Basement swimming pools in Chelsea
- Basement gyms in Chelsea
- Basement cinema rooms in Chelsea
- Basement golf simulator rooms in Chelsea
- Luxury painting and decorating in Chelsea
Extensions nearby
- House extensions across London
- House extensions in Fulham
- House extensions in Kensington
- House extensions in Clapham
- House extensions in Notting Hill
- South Kensington
- Kensington
- Fulham
- Knightsbridge
Further reading, from the journal
How far back can I extend a Chelsea house?
Usually no further than the general line of your neighbours’ extensions.
That is the first test in the borough’s Policy CD13.
We measure the neighbouring rear additions before we draw.
Can a Chelsea extension go up to the roof?
Rarely. CD13 resists an extension that reaches the main eaves or parapet.
Most Chelsea extensions stay at garden or lower ground level.
Can I add a conservatory to a Chelsea house?
At garden level, often yes.
It is resisted on a roof, high above the garden, or on a corner.
Can I build a kitchen extension and a basement together in Chelsea?
Yes. We did exactly that on a Chelsea house.
The basement follows Policy CD11, one storey under half the garden.
The extension follows CD13. We usually apply for both together.
What does a kitchen extension in Chelsea cost?
Our 2026 cost guide puts a rear kitchen extension at £160k to £250k.
A wraparound runs £200k to £320k as a project total.
Tell us about your home in Chelsea.
Your name and one way to reply are enough. It goes straight to the studio.
- Already have an architect or designer? We build to their design. Working with your designer
- An NDA on request, and your home is never published without your consent. How we work in confidence