Open-Plan Conversions Barnet

GS Renovation opens up Barnet homes, turning the compartmented layouts of 1930s semis into bright kitchen-diners and knock-through living spaces. From N2 and N3 through to the interwar houses of Mill Hill and NW11, our founder's 30+ years of structural experience means the walls come down safely and the new steel disappears into the ceiling line.

In Barnet, 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 Barnet: 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 Barnet 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 Barnet 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.

Knock-throughs in Barnet's 1930s semis

The classic Barnet semi separates a front reception from a rear dining room with a load-bearing spine wall, and knocking the two together is the single most popular change we make in N3, N12 and NW4. Because that wall carries floor and roof loads, the opening needs a properly sized steel beam, not just a lintel, and the engineer specifies the section to span the full width of the room.

For a true open-plan feel we can take the wall out completely and set a flush beam up into the ceiling zone, so the finished space reads as one room with no downstand interrupting the line. Where clients prefer broken-plan, we form a wide structural opening or frame it with a Crittall-style glazed divider, keeping a sense of separation while the light still travels through the generous interwar footprint.

Housing in Barnet

For Barnet the Council Tax list gives about 160,480 homes; by type 50% flats and 50% houses, by age 46% post-war, 34% interwar and 20% older than 1919. Since many homes here are flats, opening up a flat in Barnet changes its fire escape route, which building control checks.

Opening up a Barnet ground floor that is a flat

50% of Barnet's homes are flats, so the ground floor you want to open up may be a garden flat in a converted house rather than a whole house. That changes the scope before any steel is sized. The structural principle is the same, but the loads above belong to other owners, the lease decides whether you may alter the structure at all, and the garden side of the flat is where the planning question sits. Plan the knock-through and any new doors to the garden as one design, because the rear opening is the part of the job that can need permission.

Barnet Council's own appraisal for Golders Green Town Centre explains the reason: an Article 4 direction is not applied there because various permitted development rights are automatically removed on flats. The same principle applies to flats across the borough. A house owner can often widen a rear window into folding doors without an application, whereas a flat owner making the same change is altering the outside of the building and usually needs planning permission. Apply with the drawings the engineer's design is based on, so the opening width that is approved and the beam that is supplied match.

Kitchen-diners and building control in Barnet

Opening up the ground floor of a Barnet house is controlled under the Building Regulations rather than planning, so Barnet Council building control inspects and certifies the beam and its bearings. Planning only enters the picture if you are also altering the exterior, and homeowners within Hampstead Garden Suburb's conservation area should note that its controls apply to the outside of the property, not to internal steelwork like this; a listed home needs listed building consent inside too.

Most of these knock-throughs involve the spine wall, but where an opening reaches a party wall shared with the neighbouring semi the Party Wall Act applies and you serve notice first. We prop the floor above, remove the wall in stages, bed the steel on padstones and then handle the plastering, flooring and making good so your new kitchen-diner is finished, not just structurally opened up.

• Making good, plastering and decorating the finished space
• Zoned lighting circuits and dimming for a multi-use room
• Beam depth checked against existing ceiling heights

VOA Council Tax stock of properties, March 2025, for all 42 statistical areas in Barnet. Counts rounded by the VOA.

Next steps that tend to follow open-plan conversion in Barnet: home renovation in Barnet, our Barnet area guide, builders in Barnet, converting a garage into living space, how we handle open-plan conversion across London and Building Regulations Explained.

Why Barnet Homeowners Choose GS Renovation

Barnet homeowners choose GS Renovation for open-plan conversions because we run the whole thing as one job: engineer-sized steel and Barnet Council building control arranged, then our own trades taking the wall down and finishing the space. Expect flush beams hidden in the ceiling, tidy working in your home, and our founder's 30+ years on the tools.

Reviewed jobs near Barnet

2 MyBuilder reviews from Barnet, with each customer's own job title:

• Install new kitchen, Barnet, 15 Apr 2022 (5 out of 5)
• Bathroom Refurbishment, Barnet, 14 Oct 2021 (5 out of 5)

Read all 31 on our reviews page.

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.