House Extensions Soho

GS Renovation builds extensions in Soho and the W1 postcode where one is possible at all: almost every home here is a flat in a conservation area, so most schemes are small rear or roof additions to the few whole houses, agreed with Westminster and any freeholder. We handle everything from foundations and steelwork to the final fit-out, and we guide you through planning or permitted development from the very start.

In Soho, 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 Soho: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Rear additions, not side returns, for Soho's few houses

Where you own one of Soho's few whole houses, the space to extend is usually a small rear yard or an existing rear addition rather than a garden. Soho's buildings stand wall to wall on narrow plots, so the side return found behind a Victorian terrace elsewhere in London rarely exists here. Rebuilding or filling that rear part can widen a cramped kitchen into a proper kitchen-diner. We dig and lay the foundations, build the walls, install the steel beams needed to open up the old rear wall, and form the new roof, often with rooflights to draw daylight deep into the plan.

Whether your extension is permitted development or needs a full planning application depends on the property. Soho lies within Westminster's Soho Conservation Area and many buildings are listed. A modest single storey rear extension to a whole house can still be permitted development in a conservation area unless an Article 4 direction removes it, but side, two-storey and roof extensions are not, flats have no householder permitted development at all, and any work to a listed building needs listed building consent. We assess this before any design money is spent and build to the approved drawings, so you know exactly where you stand rather than discovering a problem halfway through the build.

Housing in Soho

The Fitzrovia West & Soho statistical area counts roughly 6,840 homes for Council Tax; 48% are older than 1919, 5% interwar and 47% post-war, with 98% flats and 2% houses. A flat in Soho has no householder permitted development rights, so extending one needs planning permission and the freeholder's consent, which matters here because most homes are flats.

Extending in Soho when only 2% of homes are houses

In Soho 98% of homes are flats and 2% are houses, so an extension here is more likely to belong to a flat, which has no householder permitted development rights. Any extension to a flat is a planning application to Westminster City Council. Westminster's conservation area guidance says extensions should respect the scale and proportions of the existing building and must be architecturally subordinate to it, and that full width rear extensions are generally not acceptable, except in certain circumstances at basement level. For a Soho rear yard that points to a modest addition that leaves part of the original back wall visible.

Soho has its own neighbourhood plan, adopted on 8 October 2021, and applications in the area must respond to its policies as well as the City Plan. The current City Plan was adopted by full council on 21 January 2026. An extension application in Soho therefore answers to three documents, and the design statement has to address the neighbourhood plan policies directly. We read those before the architect sets the footprint, so the steel, foundations and programme are planned for a scheme that can be approved.

Two storey rear additions in W1

Where the plot allows, a two storey rear addition adds a bigger kitchen below and a bedroom or bathroom above in a single build, and in Soho it always needs planning permission from Westminster. On such tight plots it needs careful thought about foundations, party walls and the impact on neighbouring light. Because the dividing walls are shared, you serve the Party Wall Act notices as building owner (or your surveyor does), and the surveyors usually record the condition of the buildings either side before we break ground; we give you the drawings and programme the notices need and build to any award.

Once the shell is up, our own trades take over the fit-out: plastering, joinery, electrics, plumbing, heating, tiling and decoration, all finished to match the character of the original house. We keep the site clean and secure, which matters on the busy central streets of W1 where space is tight and neighbours are close. From the first sketch to building control completion, you deal with one team that stays accountable throughout.

Kitchen extensions in Soho

98% of homes in Soho are flats, and a flat has no householder permitted development, so a ground-floor flat's kitchen extension needs planning permission from Westminster City Council and the freeholder's consent. With so few houses here, the realistic kitchen gain in most Soho homes is a better layout inside the flat rather than an extension. The fit-out is priced on its own page, kitchen renovation in Soho; the build figures are in the table above.

• Steel goalpost frames where the rear wall opens up
• Full fit-out, finishing and making good
• Roof works and structural alterations at roof level

VOA Council Tax stock of properties, March 2025, for the Fitzrovia West & Soho statistical area, which also covers west Fitzrovia. Counts rounded by the VOA.

Plenty of Soho projects start with one job and grow, so it helps to see RSJ and steel beam installation in Soho, house extensions across Westminster, wraparound extensions, garage conversions in London, house extensions across London and Bifold vs Sliding Doors.

The GS Renovation Difference in Soho

Extending in central Soho means working within a conservation area, on a tight plot, with shared walls and close neighbours. GS Renovation explains the planning route plainly, then builds the structure and the finish under one roof, backed by our founder's 30+ years on the tools, giving you clear pricing, tidy working and a build that respects the period home.

• Foundation depth set after trial holes, drains and trees are checked
• Insulation and thermal detailing to current regulations
• Aftercare and snagging support once the job is finished

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.