Open-Plan Conversions Hayes
Open-plan kitchen, diner and living conversions in Hayes, 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 Hayes homes, opening up UB3's 1930s semis and interwar houses into bright kitchen-diners and connected living areas. We handle the knock-throughs, the steelwork and the sign-offs that turn compartmented interwar rooms into modern family space.
In Hayes, 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 Hayes: 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 Hayes 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 Hillingdon 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.
Open-plan living in Hayes interwar homes
Interwar houses in Hayes were designed as a series of separate rooms, a front reception, a rear dining room and a small kitchen, connected by narrow doorways. Owners across UB3 increasingly want these opened into a single kitchen-diner or a through-lounge that makes the most of the generous rear plots. Because the wall between them usually carries the floor above, a knock-through here is genuine structural work.
We open these homes up in different ways to suit the house and the way you live. A full knock-through with a flush steel beam gives a clean, uninterrupted room; a broken-plan approach keeps zones loosely defined; and Crittall-style glazed dividers let light flow through while retaining a degree of separation. Whichever route suits your Hayes home, a structural engineer sizes the beam and specifies its bearings first.
Housing in Hayes
Around 16,650 homes make up Hayes on the valuation list; 42% are flats and 58% houses, and 4% date from before 1919, 44% from between the wars and 52% from after 1945. A semi in Hayes usually opens up with one beam, one end on the shared wall, and 30% of homes here are semi-detached.
Opening up a three storey Hayes house built since 2000
28% of homes in Hayes were built in 2000 or later, and where a newer house has three storeys, open-plan work changes. In a house with a floor high above the ground, the enclosed hall and stair are the escape route from the top bedrooms, and the doors off it are fire doors for a reason. Taking out the hall wall to open the ground floor removes that protected route, so building control will expect a different arrangement, which can mean sprinklers, a fire separated kitchen or a new enclosure on the upper floors. Agree that strategy before the walls are drawn out.
The design then has to go to Hillingdon properly. A full plans application is for domestic or commercial works and requires detailed plans and structural calculations for approval. For a Hayes townhouse that means the engineer's beam design and the fire strategy on the same set of drawings, which lets the inspector judge them together. Newer houses may also have engineered timber joists and a ventilation system with ducts in the ceiling, and both limit where a beam can go and how deep it can sit.
Beams, propping and sign-off in UB3
The heart of an open-plan conversion is the steel beam that replaces the removed wall. The engineer sizes it for the loads it carries, it bears onto padstones at each end, and we install it by propping the floor above, taking the wall down in stages and bedding the steel securely before the props come out. Done properly, the finished ceiling runs flush with no visible downstand.
Open-plan work in Hayes is controlled under the Building Regulations, so Hillingdon Council's building control inspects and certifies the beam and its bearings; it does not need planning permission, though a listed house needs listed building consent. Where the beam bears onto the party wall shared with an attached neighbour, the Party Wall Act applies and you serve notice first as building owner. We give you the drawings it needs and deliver the whole conversion as one accountable team.
- Utility and boot room space carved out of the new layout
- Openings formed in stages to keep the home usable
- Making good, plastering and decorating the finished space
VOA Council Tax stock of properties, March 2025, for Hayes End, Hayes Town North, Hayes Town & Lake Farm and Hayes South. Counts rounded by the VOA.
Why Choose GS Renovation in Hayes
Hayes homeowners choose GS Renovation for open-plan conversions because we get the structure right before the finish. One team appoints the engineer who designs the beam, plans around the party wall notice you serve on an attached neighbour, and handles Hillingdon building control and the full build, with careful propping and tidy working in your home, and our founder's 30+ years of 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…
It's the second time I have hired George and he has been absolutely professional and the work he did resembles perfectly what I had in mind. Being an…
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 Hayes
What is the going rate for open-plan conversion around Hayes?
Open-plan conversion around Hayes typically costs £3,000 to £8,000 or more (indicative), but scope varies more than the market does. Two Hayes jobs of the same size can be different work, because the protected route from the stairs decides how open the plan can be. GS Renovation surveys and prices each on its merits at UB3, with the Hillingdon Council building control fee shown separately.
Can I get a flush ceiling when opening up my Hayes kitchen-diner?
Usually, yes. In most Hayes interwar homes the steel beam can be sized to sit up within the floor zone so the finished ceiling runs flush with no downstand hanging below. The structural engineer confirms this when sizing the beam for your specific openings and loads, and Hillingdon building control signs off the completed installation.
Should I make a kitchen-diner or a through-lounge in my Hayes semi?
It depends on which wall you remove and how you live. Taking out the spine wall between the two receptions gives a long through-lounge; opening the rear dining room into the kitchen gives a kitchen-diner onto the garden. Both are structural in most interwar Hayes semis. Doing both at once changes how the first floor is carried, so the engineer designs them together, never one at a time.
Will an open-plan ground floor be colder in my Hayes house?
It can, because one large room loses the internal walls that held heat in and often gains a big glazed opening to the garden. Radiator output has to be recalculated for the new volume, and underfloor heating is worth considering while floors are up. Decide this before the beam goes in, so pipe runs can cross the opening before the floor is made good.
Does the staircase limit how open-plan a Hayes semi can go?
In a two-storey Hayes semi, removing the hallway walls is not caught by the Part B rule for houses with a floor more than 4.5 m above ground, so a fully open stair is possible. Add a loft room later and that changes: a third storey means the escape route needs protecting again. If a loft conversion is on the cards, plan the ground floor with it in mind.
Why do floor levels differ between rooms I want to join in my Hayes house?
Interwar houses often have suspended timber floors in the front rooms and a solid concrete floor in the kitchen, so there can be a step or slope where they meet. Joining them means packing up the timber, screeding the concrete, or a mix of both, and any underfloor heating adds its own depth. Settle levels before ordering flooring, because the whole run must sit flat.
How soon can open-plan work start in Hayes once Hillingdon has been told?
Under a Hillingdon building notice, work can start subject to giving 48 hours notice. That speed is useful when the steel is already ordered and the engineer's calculations are ready. The trade off is that Hillingdon Council does not issue plans approval on a building notice, so the first check of the design happens on site. For a straightforward knock-through that is often acceptable. For a job with two beams meeting at a post, an approved design first is the safer order.
Which Hillingdon building control charge applies to a Hayes knock-through?
Hillingdon's table has two lines for openings. One covers forming a structural opening in a wall such as a simple through lounge. A second, higher total covers forming a structural opening in a wall with additional building works. Joining the front and back reception with one beam is likely to fit the first. A knock-through that also moves the kitchen, blocks a doorway or adds a post foundation may fall into the second, so list everything in the application.
Should a Hayes knock-through allow for a rear extension planned for later?
Yes, because the beam fitted now decides what the back of the house can do later. Hillingdon's Article 4 Direction removes permitted development rights for residential extensions that extend beyond the rear wall of the original dwelling by more than 4 metres, and it has applied borough wide since 22 September 2014. If a deeper extension is likely, ask the engineer to size the new steel and its bearings for the rear wall coming out afterwards.
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