Open-Plan Conversions New Barnet
Open-plan kitchen, diner and living conversions in New Barnet, steel, floors, heating and finishes as one job.
- Rated 4.9 from 31 reviews on MyBuilder
- London guide: £3,000 to £8,000+
- Free site survey, itemised quote
Opening up a New Barnet terrace usually means one of two moves: through the wall between the front and rear reception rooms, or through the back wall into a side return infill. Both are structural, both need a beam sized by an engineer, and both change how the house heats and sounds. We do the structure and the finish as one job.
In New 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 New Barnet: the structural engineer we appoint designs the steel, we install it, and building control signs it off.
Price guide
| Work | Indicative London range |
|---|---|
| Open-plan conversion, steel beam and finishing | £3,000 to £8,000+ |
Indicative London ranges (MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: Open-Plan Kitchen-Diner Ideas.
How the job runs
- Free site survey at your New Barnet address, covering the walls, services and floor levels, and an itemised quote.
- 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.
- Props in, opening cut, beam on padstones; then floors, heating and electrics are joined up.
- Building control inspects the steel before it is covered. We finish the room, and the completion certificate follows.
The two knock throughs that suit an EN4 terrace
On the period houses near the station and in the interwar semis, the through lounge is the classic alteration, taking the wall between the two reception rooms out so light from the bay reaches the back of the house. It works, but be honest about the trade off before you commit: you lose the only quiet room, the hall noise carries, and the pair of chimney breasts either side of that wall usually have to go too, which is a separate structural exercise. Plenty of owners in EN4 do it and never look back. A few wish they had kept a door.
The second move suits the rear better. A Victorian terrace has a back addition with a narrow strip of land beside it, and infilling that side return widens the rear of the house by two metres or so, turning a corridor kitchen into a room. The wall between the old kitchen and the new infill comes out on a beam. Watch the floor levels: the back addition often sits a step below the main house, and the level has to be resolved in the screed rather than with a threshold strip.
Housing in New Barnet
By the valuation list's count, the New Barnet and Hadley Wood statistical areas holds about 10,670 homes, 50% houses and 50% flats; by age, 17% were built before 1919, 32% between the wars and 52% since 1945. Opening up a flat in New Barnet changes its fire escape route, which building control checks, which matters here because many homes are flats.
Open plan living in a New Barnet flat
Half of New Barnet's homes are flats, and opening a kitchen into the living room of a flat is a fire question before it is a design one. In a flat the usual escape is along a protected entrance hall, so the kitchen, where fires start, sits off that route behind a door. Remove that separation and a cooking fire can sit between the bedrooms and the front door. Building control can accept an open layout, but it needs an agreed alternative such as enhanced detection or a sprinkler or mist system, settled before the wall comes out.
Sound is the second issue. In a post-war New Barnet block with concrete floors, footsteps on a hard finish still reach the flat below, and an open plan room with a hard floor reflects sound more than two carpeted rooms did. The lease may set a floor specification, and even where it does not, an acoustic underlay under timber or tiles is the fix. Plan where the television, the extractor and the dining table sit relative to the bedroom of the flat below, because that neighbour hears the new layout too.
Structure, services and consents across New Barnet
The steel is sized by a structural engineer we appoint, bears on padstones cut into sound masonry, and goes in behind full propping with the wall taken down in stages. Barnet Council building control inspects the beam and the bearings before they are covered and issues the completion certificate. Where the beam bears into a party wall, and in a terrace it usually does at one end at least, the work is notifiable under the Party Wall etc. Act 1996 and the notice is served by you before we start.
Services are what people forget. The wall coming out held the radiator, the light switches and often the hall lighting circuit, and a single larger room needs its heating output recalculated rather than assumed. Open plan also changes escape and fire separation if the stair now opens into the same volume, which matters in a New Barnet terrace where the stair rises from a narrow hall that the new opening may join to the living space. We raise that with building control at plan stage instead of discovering it at the final inspection.
- Lighting, heating and electrical reconfiguration
- Heat loss and acoustic considerations before the wall comes out
- Level flooring and threshold removal across the whole space
VOA Council Tax stock of properties, March 2025, for the New Barnet and Hadley Wood statistical areas, which also take in East Barnet and Hadley Wood. Counts rounded by the VOA.
Why Choose GS Renovation in New Barnet
GS Renovation opens up New Barnet terraces as a structural job with a decent finish on the end, not the other way round. One team handles the engineer's beam, the propping and staged demolition, the heating and electrical alterations, the plastering and the Barnet building control sign off, with the party wall information your neighbours need prepared for you. Founder led, 30+ years of hands-on experience.
The kitchen has been fitted to the high standard. Saaid was polite, professional, tidy, he pays attention to a little details that make huge…
We loved working with George and Ibrahim and would highly recommend them. They have done splendid job on our new kitchen refurb which including new…
Saiid did a complete refurbishment of our small bathroom. This involved ripping out the existing bath/shower, basin, toilet, pipework, and tiles and…
FAQ
Frequently Asked Questions about Open-Plan Conversions New Barnet
How accurate is an open-plan conversion quote for a New Barnet house?
The accuracy of an open-plan conversion quote in New Barnet depends on the information behind it. A phone figure will move; one written after GS Renovation has checked the EN5 property usually does not, because what the New Barnet dividing wall carries decides the beam, and that is only visible on site. The Barnet Council building control fee is shown separately, and the range to compare against is £3,000 to £8,000 or more (indicative).
Should I knock both reception rooms into one in my New Barnet terrace?
It depends on whether you can spare the second room. A through lounge brings the bay window light all the way to the garden end and suits how most families actually live. Against that, you lose the only door you can shut, noise from the front door and stairs travels the full depth of the house, and the room is harder to heat evenly. In an EN4 terrace with three bedrooms and no study, that quiet front room is often worth more than the openness. Walk a finished one before deciding.
Can the kitchen be opened into the dining room in an interwar New Barnet semi?
Usually. The wall between kitchen and dining room in these semis often carries the bathroom floor above, so it needs a beam sized by the engineer. Cooking then shares the room with the table, which makes extraction ducted to outside more important. Plan the hob and duct route before the steel goes in, since the duct may need to pass where the beam will sit.
How does the ceiling look after an open-plan conversion in New Barnet?
Rarely perfect without work. The two rooms often have slightly different ceiling heights, and in older houses the lath and plaster tends to crack once the wall is gone, since it loses a support. A downstand beam leaves a visible strip. We usually replaster or overboard the whole ceiling so the room reads as one, and decide flush or downstand before ordering the steel.
What order does an open-plan conversion follow in a New Barnet house?
Engineer's design, then building control application and any party wall notice. Services in the wall are rerouted next, then props go up and the wall comes down in stages. The steel is set on padstones, and building control inspects the bearings. Only then does first fix start, followed by plastering, flooring and finally the kitchen or joinery. Skipping ahead means ripping out finished work.
Will the floorboards join up when my New Barnet rooms are opened into one?
Not always. Where the old wall stood there is often a strip of different board, a timber sole plate or a gap, and the two rooms may sit a few millimetres apart in height. Old boards can be replaced or relaid, but many owners lay a new floor across the whole space over a ply deck. We check the joists beneath at the same time, especially where the wall was taking some of their load.
What happens to the heating when a post-war New Barnet ground floor is opened up?
The radiator on the removed wall goes, and a concrete floor gives you another option. Where the strip where the wall stood has to be screeded anyway, an underfloor heating loop can go into a new screed across the whole room, as long as the floor level and insulation allow it. In New Barnet 52% of homes were built after 1945. The heating engineer sizes the output for one room, not two.
Can an interwar New Barnet semi keep a separate sitting room after opening up?
Yes, and it is worth planning. Interwar semis have a front room, a back room and a kitchen, and the common scheme joins the back room and kitchen while the front room keeps its door. In New Barnet 32% of homes were built between 1919 and 1939. That leaves a room for television and guests, keeps the hall enclosed and puts the new steel only where the kitchen needs it.
Is open plan harder in a New Barnet terrace than in a semi?
Structurally the two are similar, but the neighbours are not. A beam across a mid terrace usually lands in both party walls, so both adjoining owners receive notice from the building owner and both sides of the house are opened at once. In New Barnet 15% of homes are terraced houses and 32% are semi-detached or detached. A semi has one party wall, so one neighbour is involved, and a detached house has none.
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