Staircase seen from above, turning around a tall void.

Loft conversions in Knightsbridge.

Knightsbridge · SW1 · Knightsbridge townhouse, whole house refurbishmentCompleted work, photograph

Knightsbridge roofs answer to two councils. We find out which one before anything else.

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A Knightsbridge roof, and the boundary under it.

Two boroughs
Westminster east, Kensington and Chelsea west
2018
Knightsbridge Neighbourhood Plan made
Three homes
Built here by our own team

NU Projects is a design and build company in Fulham SW6, founded in 2010. We handle loft conversions, dormers and mansards in Knightsbridge SW1X, under one contract. A main dormer loft typically runs £90k to £140k. A mansard loft runs £140k to £220k. Call 020 7731 6841, and a budget estimate typically follows within seven days.

Knightsbridge straddles a borough line. The east falls to Westminster, the west and south to Kensington and Chelsea.

Both refuse extra floors on unaltered terraces. Each phrases it in its own guidance.

Most homes here are leasehold apartments in stucco terraces or mansion blocks. A managing agent usually stands between you and the roof.

The handful of townhouses near the park are the realistic loft candidates.

We have refurbished two townhouses and an apartment here, so we know these buildings.

What each council allows on a Knightsbridge roof.

Council
Westminster or Kensington and Chelsea, depending on the address. We confirm which.
Westminster side
Roof extensions are refused on complete terraces with largely unaltered roof lines.
Kensington and Chelsea side
Policy CD12 resists an extra storey wherever a group roofline is intact.
Neighbourhood plan
Westminster’s side has the Knightsbridge Neighbourhood Plan, made in December 2018.
The lease
Most homes are leasehold. A freeholder’s licence sits beside any council consent.
Listed buildings
Many are listed. Consent can reach the roof structure and top rooms.

Source: Westminster’s Roofs guide to alterations and extensions on domestic buildings. Read on 6 October 2026. Policies change, so we read them again for your address.

What a loft conversion costs in Knightsbridge.

£140k to £220kA mansard loft. A project total, from our 2026 cost guide.

A loft here is priced once both council and freeholder are known.

The guide figure is a project total.

Fees, party wall costs, contingency and VAT sit outside it.

Open the calculatorThe 2026 cost guideCan I build it here?

Which council decides a Knightsbridge loft conversion?

It depends which side of the borough line the house stands.

East is Westminster. West and south are Kensington and Chelsea.

We check the address before any drawing.

Can a Knightsbridge apartment owner build into the roof?

Only with the freeholder’s licence and planning permission.

Flats carry no permitted development rights for roof work.

The managing agent is usually the first call.

Does the Knightsbridge Neighbourhood Plan cover my roof?

Only on the Westminster side, where it was made in 2018.

It sits beside Westminster’s own roof guidance.

Is a mansard realistic on a Knightsbridge townhouse?

Where neighbours already have one, sometimes.

On an untouched terrace, both councils normally refuse.

Listed townhouses add a further consent.

Tell us about your home in Knightsbridge.

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