Open-Plan Conversions St John's Wood

GS Renovation turns the compartmented layouts of St John's Wood's mansion flats and villas into bright, open living space. We knock through reception rooms, open kitchens to dining areas, and design broken-plan layouts, all engineered and signed off so the structure is never compromised.

In St John's Wood, a knock-through finished as one room typically costs £3,000 to £8,000 or more, including the steel beam (indicative London ranges, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in St John's Wood: the structural engineer we appoint designs the steel, we install it, and building control signs it off.

How the job runs

1. Free site survey at your St John's Wood address, covering the walls, services and floor levels, and an itemised quote.
2. The engineer we appoint sizes the beam, and the work is registered with Westminster City Council building control or an approved inspector. On a shared wall you serve the party wall notice as building owner; we supply the drawings.
3. Props in, opening cut, beam on padstones; then floors, heating and electrics are joined up.
4. Building control inspects the steel before it is covered. We finish the room, and the completion certificate follows.

Open-plan layouts for St John's Wood flats and villas

The classic St John's Wood mansion flat or villa was built as a series of separate rooms: formal receptions, a long hall and a service kitchen at the back. A common conversion joins the two receptions into one long room, or opens the rear reception into the kitchen to make a single kitchen-diner that catches light from both ends. We design each layout around what the walls are actually holding up.

Because the wall between those rooms is usually load-bearing, every knock-through starts with an engineer sizing a steel beam to carry the floor and wall above. The beam bears onto padstones at each end, we prop the structure while the wall comes out in stages, and then lift the steel into place. For a broken-plan feel, some St John's Wood clients prefer a Crittall-style glazed screen or a part-width opening, keeping zones distinct while the light still flows through.

Housing in St John's Wood

St John's Wood has about 8,840 homes on the Council Tax list: 23% pre-1919, 31% interwar and 46% post-war, with flats making up 90% and houses 10%. Most homes here are flats, and opening up a flat in St John's Wood changes its fire escape route, which building control checks.

Counting the openings in a St John's Wood open-plan scheme

An open-plan replan of a St John's Wood mansion flat can involve more than one opening. Joining two receptions, opening the kitchen and widening the hall can mean three or four new openings in structural walls, and each has its own beam, bearings and fire detail. Westminster's fee schedule has a minor works charge for new openings in a structural wall covering one property with fewer than 5 openings, the same on a building notice or a full plans application. Counting the openings early tells you whether the scheme sits inside that category or has to be assessed as a larger job.

With 90% of St John's Wood homes being flats, an open-plan scheme here is usually also a licence to alter application, and a freeholder is better shown the whole scheme than a first phase. We draw every opening on one set of drawings for both the freeholder and Westminster, so neither sees a phased version that later grows. Where the replan goes beyond the openings into a full refurbishment, Westminster's schedule has a separate residential refurbishment charge for work below a set cost, the same on either route and with no separate inspection charge.

Consents and clean delivery in St John's Wood

An open-plan conversion in a semi-detached villa or a divided house often loads the shared party walls, whether the beam bears into them or a new opening sits alongside, so the work is notifiable under the Party Wall Act. You serve notice on the neighbours in good time, as building owner or through your surveyor; we give you the drawings the notice needs and build to any award. Getting that right early keeps the project moving and keeps your neighbours onside throughout the build.

Knocking through is internal structural work, so it falls under the Building Regulations and Westminster City Council's building control, not planning, and that is true in a conservation area too; a listed building needs listed building consent for internal as well as external works that affect its character. Because these are occupied family homes, we phase the demolition to keep dust down, seal off the work area, protect original floors and cornicing where it stays, and manage the beam, propping and inspections through to the completion certificate.

• Ventilation and extraction planned for an open kitchen
• Lighting, heating and electrical reconfiguration
• Rooflights and glazed roofs to bring light deep into the plan

VOA Council Tax stock of properties, March 2025, for St John's Wood North and St John's Wood South. Counts rounded by the VOA.

If you are weighing up options for your St John's Wood property, it is worth reading home renovation in St John's Wood, open-plan conversion across Westminster, side return infills, garage conversions, our London open-plan conversion page and RSJ & Load-Bearing Walls.

The GS Renovation Difference in St John's Wood

St John's Wood homeowners choose GS Renovation for open-plan conversions because one team handles layout, structure and finish together. We appoint the engineer who calculates the beam, install the steel and see building control through, then make good so the new space is ready to decorate. Backed by our founder's 30+ years on the tools, and known for tidy, respectful working in occupied houses.

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.