Panelled reception room with a lit fire and herringbone parquet.

Extensions in Knightsbridge.

Knightsbridge · SW1 · Knightsbridge apartmentCompleted work, photograph

Knightsbridge is mostly apartments, with a few townhouses near the park. Extensions here go sideways, upward or below, rarely into a garden.

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Adding space where gardens are scarce.

Three projects
Two townhouses and a lateral apartment here
Two councils
Which one depends on the address
SW1X · SW3 · SW7
Mansion blocks, stucco and townhouses

NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle house and kitchen extensions in Knightsbridge SW1X, 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.

We have finished three projects in Knightsbridge. Two were townhouses, one a lateral apartment.

That mix is honest about the place. Most homes are flats in stucco terraces and mansion blocks.

In a flat, extending usually means going sideways. A lateral apartment takes in the matching floor next door.

Townhouses are fewer, and many are listed. Gardens are small, so space is often found below or in the roof.

First we confirm which council rules the address. Kensington and Chelsea lies west and south, Westminster east.

What the council allows in Knightsbridge.

Council
Kensington and Chelsea to the west and south. Westminster to the east and the park side.
Listed interiors
Many buildings here are listed. Consent then covers plaster, panelling, stairs and chimneypieces.
The lease
A freeholder’s licence is usually needed. The managing agent’s rules apply as well.
Party floors
A floor between two flats is a party structure. Work to it needs notice.
Rear additions
On the Kensington and Chelsea side, Policy CD13 keeps them below the eaves.

Source: Kensington and Chelsea’s Local Plan 2024 Policy CD11, and Westminster’s City Plan Policy 50. Read on 3 October 2026. Policies change, so we read them again for your address.

Built in Knightsbridge.

Entrance hall with a marble floor and a curving staircase.

Knightsbridge·Apartment

Knightsbridge apartment

A lateral apartment here in Knightsbridge, stripped back and rebuilt over about 40 weeks.

See the project
Swimming pool lined in marble with a lit ceiling above.

Knightsbridge·Townhouse

Knightsbridge townhouse, pool and wine room

A Knightsbridge townhouse we took from first survey to handover.

See the project

Completed work, photographs

What a house extension costs in Knightsbridge.

Lateral work is priced with lease, licence and party wall costs in view.

Fees, contingency and VAT sit outside any build figure.

Open the calculatorThe 2026 cost guideCan I build it here?

Can I extend my Knightsbridge flat into the one next door?

Often, as a lateral apartment, if both leases and the freeholder allow it.

Opening the wall between them needs party wall notice.

Listed consent applies too if the building is listed.

Which council decides a Knightsbridge townhouse extension?

It depends on the address. Kensington and Chelsea covers the west and south.

Westminster covers the east and the side by the park.

Their rules differ, so we check before drawing.

Can a Knightsbridge townhouse with a small garden still be extended?

Sometimes at the back, but small gardens limit it.

Space below ground or in the roof is often the better route.

Each has its own policy, which we test first.

Will the managing agent affect works in a Knightsbridge apartment?

Yes. Managing agents set working hours and lift use.

Noisy work often has its own window, written into our programme.

Tell us about your home in Knightsbridge.

Your name and one way to reply are enough. It goes straight to the studio.

A phone number or an email is enough. We only need one.

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What is the work?

We call you back within the hour, in working hours. Your details go to the studio and our email system. Read the privacy note.