RSJ and Steel Beam Installation New Cross
Steel beam and RSJ installation in New Cross, designed by the engineer we appoint and signed off by building control.
- Rated 4.9 from 31 reviews on MyBuilder
- London guide: £1,500 to £4,000
- Free site survey, itemised quote
GS Renovation installs steel beams and RSJs across New Cross, where the bay-fronted Victorian and Edwardian terraces among SE14's flats are built around rear closet wings and side returns. We remove load-bearing walls safely and open these period homes up without compromising the fabric above.
In New Cross, a steel beam for one opening typically costs £1,500 to £4,000 fitted and signed off, or £2,500 to £6,500 or more for a full knock-through with the engineer's fee and making good (indicative London ranges, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in New Cross.
Price guide
| Work | Indicative London range |
|---|---|
| Steel beam, one opening: supply, install, sign-off | £1,500 to £4,000 |
| Full knock-through with engineer and making good | £2,500 to £6,500+ |
Indicative London ranges (MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: RSJ & Load-Bearing Walls.
How the job runs
- Free site survey at your New Cross address and an itemised quote.
- The engineer we appoint sizes the beam, and the work is registered with Lewisham 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 go in, the opening is cut and the beam is set on padstones, packed tight above.
- Building control inspects the steel before it is covered. We make good, and the completion certificate follows.
Sizing steel beams for New Cross terraces
Every RSJ we fit in New Cross starts with a structural engineer's calculation, not a guess. In these Victorian and Edwardian terraces the wall between the two reception rooms usually carries the first-floor joists, the chimney breast and part of the roof, so the beam has to be sized for those exact loads. We set the steel onto concrete padstones spread across sound brickwork, giving the bearing the strength it needs at each end before any masonry is removed.
Because SE14 houses were built with solid walls rather than cavities, the loads travel straight down through the original London stock brick. We check the pockets we cut, confirm the padstone size against the engineer's figures, and only then transfer the weight onto the new beam. Getting the bearing right at this stage is what keeps the floors above level and the plaster crack-free for years afterwards.
Housing in New Cross
About 12,080 homes are listed for New Cross, and the mix is 28% houses to 72% flats, with 49% built after 1945, 2% in 1919 to 1939 and 43% earlier. Where most homes are flats, a beam in a leasehold flat in New Cross needs the freeholder's licence for alterations, since the lease usually keeps the structure with the freeholder.
Beams over the shopfronts on New Cross Road
Lewisham's Hatcham conservation area, designated in 1990, is made up of commercial buildings on New Cross Road with terrace housing behind. In a New Cross shop with flats above, the whole front wall of the upper floors sits on a beam across the shop opening. That beam may be old timber, cast iron or an early steel, and it is often hidden behind a fascia. When a shop is refitted, a unit is converted or the front is re-glazed, the structural engineer we appoint needs to see that beam before anything is designed. A new opening width or a replacement beam changes the load path for every floor above.
The front of that building is also where planning comes in. Lewisham says flats or subdivided houses in conservation areas do not have permitted development rights and must seek planning permission for changes to the exterior, and a new shopfront opening changes the exterior of the building that holds those flats. Lewisham also requires a heritage statement for all planning applications affecting buildings in conservation areas. So a new shopfront opening with fresh steel behind it runs in a set order: survey of the existing beam, planning with the heritage statement, then the engineer's final design and the building control application.
Safe wall removal and propping in New Cross
Before a single brick comes out, we install temporary propping on both sides of the wall, supporting the joists above through Acrow props and strongboys bearing onto proper needles. In an occupied New Cross terrace this staged approach matters, because the family upstairs is carried safely at every point while we demolish. We take the masonry down in controlled sections rather than pulling a wall out in one go.
Many New Cross homes share a party wall with the neighbour, since the dividing wall and the chimney stack often sit astride the boundary. Where that is the case the Party Wall Act applies, and you, as building owner, serve the notices before work starts, with the drawings we supply. Building control inspects the beam and its bearings, and we book those inspections so your steel is signed off and recorded on completion.
Beam choices worth thinking about
You have more say over a steel installation than most people realise. Whether the beam is left as a downstand below the ceiling or lifted flush into the floor above is a genuine choice, and it affects both cost and headroom. A flush beam means cutting the joists and hanging them off the steel, which takes longer but leaves a clean unbroken ceiling line right across the room.
The second choice is exposure. A painted or blasted steel left on show suits some SE14 houses and removes the need for boxing in, though it still needs fire protection where the regulations call for it, usually intumescent paint rather than casing. The third is whether short returns of wall stay at each end. All three go to the engineer before design, because each one changes the section size and sometimes the padstones. Where a beam will be visible, we would rather agree its finish before it is fabricated than paint over a decision afterwards.
- Ceiling and floor levels resolved where the beam sits below joists
- Making good, plastering and finishing around the new steel
- Load-bearing wall removal and knock-throughs
VOA Council Tax stock of properties, March 2025, for New Cross Gate, New Cross South and Telegraph Hill. Counts rounded by the VOA.
Trusted RSJ and Steel Beam Installation in New Cross
New Cross homeowners choose GS Renovation because we treat structural work as structural work. One team handles the propping, the steel, the padstones and the building control sign-off, working to the calculations of the engineer we appoint, and we give you the drawings for a party wall notice where the wall is shared. Our founder's 30+ years on the tools means we understand exactly how these SE14 terraces are built and carry the load.
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…
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
FAQ
Frequently Asked Questions about RSJ and Steel Beam Installation New Cross
What does the RSJ and steel beam installation quotation for a New Cross home cover?
A New Cross quotation for RSJ and steel beam installation sets out scope, programme and price on one document, within £1,500 to £4,000 for one beam opening (indicative). It shows what is done, in what order and at what cost, and the order is not arbitrary: the opening is propped before any masonry comes out. Exclusions are stated plainly rather than left to be discovered once work starts at the SE14 property.
Do I need a party wall notice to remove a wall in my New Cross terrace?
Often yes. In SE14 terraces the chimney breast or the end of the new beam frequently sits in the shared party wall, so cutting into it or bearing a new beam there brings the Party Wall Act into play. You serve the notice on your neighbour as building owner before work begins; we then install the steel to the engineer's design and arrange building control sign-off.
How does a long steel beam get into a narrow New Cross terrace?
Carefully planned, because the hall in these houses turns tightly at the stair. We measure the route from pavement to room at survey. Sometimes a sash is taken out of the bay so the steel goes straight in through the window. Where no route works, the engineer designs the beam in bolted sections assembled in place, which avoids damaging finished joinery on the way.
Can an RSJ be fitted in an upper-floor New Cross flat?
Yes, but getting the steel up the common stairs is part of the design. Heavy single lengths may not turn on the landings, so bolted sections or lighter members are common. The freeholder's consent covers structural work and use of the common parts, and building control inspects the bearings like any other beam, with the flats below protected throughout.
Why does a New Cross beam sit on padstones?
Because the soft London stock brick of a Victorian wall could crush under the point load at each beam end. A concrete padstone spreads that load over a larger area of brickwork, and the engineer sizes it from the calculations. The pocket is cut, the padstone bedded level, and the steel packed tight onto it before the props are released and the inspector sees the bearing.
How long do the props stay in after a New Cross steel beam goes in?
Until the packing between beam and padstone has gained strength and building control has inspected the bearings. Pulling props early can let the steel settle onto soft packing and crack the ceiling above. We leave them standing until both conditions are met, then remove them gradually, checking the floor overhead as the load transfers onto the steel.
Should a New Cross beam go through full plans or a building notice?
Lewisham says that once a building notice is submitted, work can commence within 48 hours, while a full plans application gets a decision within five weeks unless a three week extension has been given. In a New Cross terrace the choice turns on how settled the design is. Where the bearing walls have been opened and the structural engineer we appoint has fixed the padstones, a building notice is quick. Where the steel carries flats above, a checked design before fabrication is the safer order.
When does Lewisham's inspector see a beam in a New Cross house?
Lewisham Building Control's typical inspection stages run from commencement of work to completion of building. A beam is not a named stage, so we tell the inspector when the steel is seated and packed and the bearings are still in view, before fire board or plaster goes on. Lewisham's own inspectors check fire safety as well as structure, so the protection to the steel can be checked on the final visit. Keep the completion certificate with the engineer's calculations for a future sale.
Can the old beam over a New Cross shop be kept when the unit is refitted?
Sometimes, but only after the structural engineer we appoint has seen it uncovered. Lewisham says building control approval is needed for the removal or partial removal of load-bearing elements, including beams, so replacing part of it or cutting it back is notifiable work. An old timber beam can hide rot at its bearings, and an early steel can be corroded where it met wet brickwork. Opening up the ends of the beam at survey tells you whether it can stay.
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