House extensions in Kensington.
Chelsea · SW3 · Chelsea basement and extensionCompleted work, photograph
Extensions for Kensington terraces, villas and garden flats. Drawn to the borough’s CD13 tests, priced open book, built by one team.
Extending a Kensington house from the back.
- W8
- Terraces, villas and garden flats
- Rear views
- They count where houses face communal gardens
- £200k to £320k
- A wraparound extension, cost guide total
NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle house and kitchen extensions in Kensington W8, 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.
Kensington runs from stucco terraces to brick villas. Many houses back onto communal gardens.
The borough treats those garden sides with care. A rear elevation can matter as much as the street front.
So an extension here is drawn to the whole terrace, not just the plot.
Many houses are split into flats. A garden flat extension needs the freeholder’s licence as well.
We price it open book, and the same team builds it.
What the council allows in Kensington.
- Council
- Royal Borough of Kensington and Chelsea, which covers all of Kensington.
- Communal gardens
- Rear elevations facing communal gardens may matter as much as fronts, the plan says.
- Symmetry
- An extension must not unbalance a terrace’s symmetry or close an important gap.
- Rear additions
- Policy CD13. Keep the even rhythm of rear additions, and stay below the eaves.
- Access
- It must not cut off rear access, for the house or its neighbours.
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 under the same rules.
Chelsea·Townhouse
Chelsea basement and extension
A kitchen extension and a new basement in Chelsea, in the same borough.
See the project
Kensington·New build
Kensington new-build houses
Two new houses we built in the same borough. Living rooms open onto light wells.
See the projectCompleted work, photographs
What a house extension costs in Kensington.
£200k to £320kA wraparound extension. A project total, from our 2026 cost guide.
A garden flat and a whole house price very differently.
Guide figures are project totals.
Fees, party wall costs, contingency and VAT sit outside both.
What Kensington owners ask about extensions.
In Kensington
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Extensions nearby
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- South Kensington
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Further reading, from the journal
Can I extend a Kensington house that backs onto a communal garden?
Often, but the garden side is judged closely.
The borough treats those rear elevations almost as carefully as the front.
We draw the extension against the whole terrace, as seen from the garden.
Can a Kensington garden flat be extended?
Sometimes, if the flat owns the garden and the freeholder agrees.
Your lease will say whether structural work needs consent.
The borough’s CD13 tests then apply as they would to a house.
Do I need planning permission for a rear extension in Kensington?
Often. Permitted development is narrower in a conservation area.
Flats have no householder permitted development rights at all.
We check the house’s status before anything is drawn.
Will my neighbours need party wall notices for a Kensington extension?
Usually, where the work is on or near a shared wall.
Notices go out before work starts.
We run that alongside the design, so it does not hold the build.
What does an extension in Kensington cost?
Our 2026 cost guide puts a wraparound at £200k to £320k in total.
Tell us about your home in Kensington.
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