House Extensions Knightsbridge

GS Renovation builds extensions across Knightsbridge, working with the period townhouses and mansion blocks of SW7 and SW1X. We handle groundworks, steel, roofing and full fit-out, and coordinate the planning and party wall side that comes with a conservation-area address.

In Knightsbridge, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Knightsbridge: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Rear and side-return extensions in Knightsbridge

Many Knightsbridge houses have a rear closet wing and a narrow side return that can be infilled to widen the kitchen and bring in light. We start with foundations and groundworks suited to the ground conditions, then form new openings with steel beams sized by a structural engineer and signed off by building control. The roof, glazing and drainage are built to match the proportions of a period property rather than fight against them.

Because many of these homes are listed and most sit within a conservation area, an extension in SW7 is far more likely to need a planning application, to the Royal Borough or to Westminster City Council on the Hyde Park side, than to fall under permitted development: a conservation area still allows a modest single-storey rear extension unless an Article 4 direction removes it, but not side or two-storey extensions, and a listed house needs listed building consent. We are always honest about which route applies to your specific house, and we shape the design around what the council is likely to accept, so you are not chasing a scheme that will never be approved.

Housing in Knightsbridge

Knightsbridge counts roughly 10,560 homes for Council Tax; 66% are older than 1919, 19% interwar and 15% post-war, with 83% flats and 17% houses. Where most homes are flats, a flat in Knightsbridge has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent.

Setting a Knightsbridge extension by the neighbours' rear line

A house extension in Knightsbridge concerns the 17% of homes that are houses, and 16% of all homes are terraced houses. Conservation area status does not take away every householder right: a modest single storey addition at the back of a house can still proceed without an application, unless that right has been withdrawn for the street. Beyond that, the borough's policy on extensions resists any extension that pushes past the general line formed by the neighbours' existing rear extensions, so your neighbours' additions set your limit. Before any design, commission a measured survey that includes the backs of the adjoining houses, and search their planning histories, so the drawings show the line the planners will measure against.

The appraisals add a second test. The Brompton Conservation Area Appraisal counts domestic extensions among the things harming the area, naming oversized rear extensions and roof additions in particular, so a Knightsbridge extension that respects the building line can still be judged on its bulk. Keeping the addition low, below the sills of the first floor windows, and built in brick that matches the rear elevation, speaks to that concern. Fix the height early in the design and hold it through the application, because each later increase reopens the question of bulk.

Planning and party walls in the Royal Borough

Whether an extension is permitted development or needs planning permission depends on the property, and in Knightsbridge the answer usually leans towards a formal application, especially where the house is listed or the elevation faces the street. We help you understand the difference between planning permission, which governs what you may build, and building regulations, which govern how it is built, so the two are never confused as the project progresses.

Extensions here almost always trigger party wall matters, because you are digging foundations near a neighbour or building up against a shared boundary in a tightly packed SW7 terrace. You serve the correct notices, work to the engineer's design and keep building control involved from foundations to completion. From first fix through to the final coat of paint, one team handles the full fit-out so the new space is finished to the standard of the house.

Kitchen extensions in Knightsbridge

83% of homes in Knightsbridge are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from the Royal Borough of Kensington and Chelsea or Westminster City Council and the freeholder's consent. Most kitchen extensions here are on the 17% of homes that are houses. The fit-out is priced on its own page, kitchen renovation in Knightsbridge; the build figures are in the table above.

Double storey extensions in Knightsbridge

Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Knightsbridge often needs planning permission from the Royal Borough of Kensington and Chelsea or Westminster City Council. It is a job for the 17% of homes that are houses; a flat cannot add a storey this way. The draft Hans Town Conservation Area Appraisal describes Sloane Street, running north to south from Knightsbridge to Sloane Square, as the central spine of the conservation area (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.

• Steel goalpost frames where the rear wall opens up
• Side-return and rear extensions
• Insulation, airtightness and thermal detailing to regulations

VOA Council Tax stock of properties, March 2025, for Hans Town and Brompton. Counts rounded by the VOA.

Two or three things usually come up alongside house extensions on a Knightsbridge job: RSJ and steel beam installation in Knightsbridge, house extensions across Kensington and Chelsea, wraparound extensions, the Party Wall Act process for extensions, how we handle house extensions across London and Bifold vs Sliding Doors.

Trusted House Extensions in Knightsbridge

Knightsbridge extensions are rarely simple, and GS Renovation manages the whole job, from groundworks and steel to roofing and finishing. We are straight about whether you need planning permission or can extend under permitted development, we coordinate the work around the party wall award, and we build to building control standards, backed by our founder's 30+ years on the tools.

• Foundation depth set after trial holes, drains and trees are checked
• Weathertight shell reached before the fit-out begins
• Registered in England, Companies House no. 14611254

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.