Open-Plan Conversions Eltham
Open-plan kitchen, diner and living conversions in Eltham, 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
GS Renovation creates open-plan spaces in Eltham, turning the compartmented ground floors of 1930s and interwar SE9 homes into bright kitchen-diners and connected living areas. We handle the knock-throughs, broken-plan layouts and Crittall dividers, with the structure behind every wall designed by the engineer we appoint.
In Eltham, 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 Eltham: 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 Eltham 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 the Royal Borough of Greenwich 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.
Open-plan layouts for Eltham's interwar houses
The 1930s semis around Eltham were laid out as separate front and rear reception rooms divided by that load-bearing spine wall, with the kitchen tucked away at the back. Knocking through to a single kitchen-diner or an open living space is a common change in SE9, but the dividing wall is structural, so every conversion starts with an engineer sizing the beam that will replace it.
Not every homeowner wants one big room. Broken-plan works beautifully in these generous Eltham layouts, using a part-height wall, a wide steel-framed opening or a Crittall-style glazed divider to separate cooking from lounging while keeping the light and space flowing. Whatever the look, the load path is engineered first, then the steel is propped, seated on padstones and hidden within the finished ceiling.
Housing in Eltham
About 14,360 homes are listed for Eltham, and the mix is 73% houses to 27% flats, with 30% built after 1945, 52% in 1919 to 1939 and 17% earlier. 35% of homes here are semi-detached; the two ground floor rooms of a semi in Eltham usually open up with one beam, one end of it on the shared wall.
How Royal Greenwich charges an Eltham open-plan extension
Where an extension opens up an existing elevation into an open-plan layout, Royal Greenwich adds half the floor area of the adjacent rooms to the chargeable area. On an Eltham semi, a small kitchen extension that takes out the back wall and joins the old kitchen and the dining room is therefore charged as a larger job than its footprint. The charges have one line for a domestic single storey extension not exceeding 10m2 and another for one of 10 to 60m2, so the rooms being opened into can move a modest scheme into the higher band.
The practical step is to measure the rooms being opened into, not just the new floor, before the application is made. The same layout decision changes what the structural engineer we appoint is designing. In a 1930s Eltham house the old back wall carries the first floor, so the opening between house and extension is a beam on two bearings. The depth of that beam decides whether the ceiling runs through flat or steps down at the old wall line. Settle the ceiling you want before the calculations, since it fixes the steel section.
Getting a knock-through signed off in SE9
An internal open-plan conversion is governed by the Building Regulations rather than planning, so there is no planning application to submit, though a listed home needs listed building consent for internal work. Building control matters, though: the Royal Borough of Greenwich or a registered building control approver checks the beam, its bearings and the padstones, and considers ventilation and any effect on means of escape in the new layout.
As the spine wall in an attached SE9 semi often meets the party wall, and one end of the new beam bears into it, the Party Wall Act commonly applies and you serve notice on the neighbour first (or your surveyor does); we give you the drawings it needs. We coordinate the engineer, the propping and the building control inspections, then finish the opening cleanly so your new kitchen-diner feels like it was always one room.
- Knock-throughs between front and rear reception rooms
- Bi-fold and sliding door openings onto the garden
- Ventilation and extraction planned for an open kitchen
VOA Council Tax stock of properties, March 2025, for all 5 statistical areas in Eltham. Counts rounded by the VOA.
Why Choose GS Renovation in Eltham
For open-plan conversions in Eltham, homeowners choose GS Renovation because one team carries the whole job: an engineer sizes the steel, and we give you the drawings for any party wall notice you serve, manage building control and prop and cut in safe stages. From full knock-throughs to Crittall broken-plan dividers, you get tidy working in an occupied SE9 home and a signed-off finish, backed by our founder's 30+ years on the tools.
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
George was very friendly and helpful from start to finish. He worked really hard to ensure our kitchen was installed to a high standard and was…
FAQ
Frequently Asked Questions about Open-Plan Conversions Eltham
What does the open-plan conversion quotation for an Eltham home cover?
An Eltham quotation for open-plan conversion sets out scope, programme and price on one document, within £3,000 to £8,000 or more (indicative). It shows what is done, in what order and at what cost, and the order is not arbitrary: the heating is resized before the space is decorated. Exclusions are stated plainly rather than left to be discovered once work starts at the SE9 property.
Can I knock my two Eltham reception rooms into one without planning permission?
Usually yes. Combining the front and rear receptions in a 1930s Eltham semi is internal structural work under the Building Regulations, not planning, so no planning application is needed, though a listed house needs listed building consent. You do need building control for the beam, and often a party wall notice, which you serve as building owner, since the dividing wall is load-bearing. We handle the building control side and give you the drawings the notice needs.
Will one big room in my Eltham semi be harder to keep warm?
It can be, unless the heating is replanned with the layout. Each room had a radiator sized for itself, and the knock-through often removes the wall one hung on. Heat losses are recalculated for the combined space and radiators resited or enlarged; if the timber floor is lifted anyway, insulating between joists or adding underfloor heating is an easy extra.
Should our Eltham knock-through join the front room or the kitchen to the dining room?
It depends which room you use least as it stands. Front to back gives a through-lounge lit from both ends and usually involves only the spine wall. Kitchen to dining makes a kitchen-diner, but pulls in plumbing, new circuits and extraction ducted outside, so it is a bigger job. Often the dining room is the one standing empty, which settles it.
What order does an Eltham open-plan conversion follow once the steel design is approved?
Services first, then structure, then finishes. Cables and pipes in the wall are diverted, props go up either side, the masonry comes out in stages and the beam is seated on its padstones. Building control sees the bearings before anything is covered. Only after that is the steel boxed in, the ceiling and wall ends plastered and the floor joined across, so no trade has to undo another.
Can the wall beside the staircase come out in an Eltham semi?
Sometimes, though it tends to carry more than it appears to. It often supports the landing and the trimmer around the stair opening, so the engineer designs for that load separately. In a two-storey house, escape windows upstairs usually satisfy building control; add a third storey and the hall must stay a protected route. If the house has a loft room making it three storeys, opening the hall into a living room changes the escape route and needs a fire strategy agreed with building control.
Is a front to back knock-through with no extension simple enough for a building notice?
Yes, as Royal Greenwich describes it. Its building control pages say a building notice is for simple work and name a through room as an example, and its charges have a separate line for a domestic through room. An Eltham ground floor opened front to back, with no extension attached, fits that description. If a kitchen move with new drainage comes with it, that is also named as simple work, but the notice should describe everything.
Does an open-plan layout in an Eltham flat affect the escape route?
It can. 27% of homes in Eltham are flats, and in an upper-floor flat the way out from the bedrooms normally runs through the hall to the front door. Opening the kitchen into that hall puts the cooking on the way out. The layout needs agreeing with building control before the wall goes, which may mean a protected lobby, a sprinkler or mist system, or a different position for the kitchen.
Is opening up a post-war Eltham house different from a 1930s semi?
Often, because the floor above may be carried another way. 30% of homes in Eltham were built after 1945, and in a post-war house the first floor can be precast concrete, or timber joists spanning side to side. A wall that would be structural in an interwar semi may carry little, and the reverse. Lift a board upstairs to see the joist direction, and let the engineer confirm what the wall is doing.
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