RSJ and Steel Beam Installation Wandsworth
Steel beam and RSJ installation in Wandsworth, 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 Wandsworth, from the red-brick mansion blocks near Battersea Park to the purpose-built period flats around Balham and Tooting. We open up load-bearing walls safely and sign every job off with building control.
In Wandsworth, 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 Wandsworth.
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 Wandsworth address and an itemised quote.
- The engineer we appoint sizes the beam, and the work is registered with Wandsworth 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.
Steel beam work in Wandsworth mansion flats
Removing a load-bearing wall inside a Wandsworth mansion flat is rarely a simple job. Many of these red-brick blocks in SW11 and SW18 hold their loads through internal masonry, so a structural engineer must size the RSJ and specify padstones before any demolition begins. We install temporary propping, take the wall down in safe staged sections and seat the new beam onto its bearings so the flat above stays fully supported throughout.
Leasehold reality shapes every step. Most flats in these blocks need the freeholder's licence to alter, and the managing agent will want the engineer's calculations and our method statement before work starts. We coordinate that paperwork, keep to the building-management rules on working hours and access, and protect communal stairwells and lifts. Building control inspects and signs off the completed steelwork so your alteration is properly certified.
Housing in Wandsworth
About 157,900 homes are listed for Wandsworth, and the mix is 28% houses to 72% flats, with 49% built after 1945, 7% in 1919 to 1939 and 43% earlier. Most homes here are flats, and a beam in a leasehold flat in Wandsworth needs the freeholder's licence for alterations, since the lease usually keeps the structure with the freeholder.
How the width of a Wandsworth beam opening changes the paperwork
Wandsworth's building control charges treat a beam differently depending on what it opens into. When the steel carries the back wall of the house over the opening into a new extension, the extension charge includes forming an opening into the extension up to 1.5m wide. A kitchen that runs into a side return, or a rear wall taken out across most of its width, is usually wider than that, and Wandsworth's schedule says an additional charge may apply for structural openings over 1.5m wide. The width the structural engineer we appoint draws is therefore settled before the application goes in, so the charge is right from the start and the opening is not trimmed later to suit a fee.
Timing matters as much as width. Wandsworth Building Control asks for the application 48 hours before starting on site and notice 24 hours before work commences. On a steel job the day that counts is the day the old wall is cut, because from then on the props carry the floors above. We work backwards from that day: steel delivered and stored, props and needles set, notice given, then the cut. On a building notice, work can start 48 hours after the notice is submitted, but only once the correct fee has been paid, so payment goes in with the notice rather than after it.
Load-bearing walls in Wandsworth period homes
Where we work on period flats and houses across SW12 and SW17, the wall between two rooms is often part of a shared party wall or carries the floor above. Under the Party Wall etc. Act 1996, cutting into a wall shared with a neighbour usually means you serve notice as building owner, so we supply the engineer's drawings, help you appoint a surveyor if one is needed and time the works around the agreed schedule. The engineer confirms the beam size and the bearing detail before anything is disturbed.
On site we prop first, then demolish in controlled stages, keeping dust down in an occupied home. The RSJ lands on padstones spread to carry the point loads into sound masonry, and we pack and pin above the beam so there is no settlement. Nothing is closed up until building control has inspected the steel, the connections and the fire protection, giving you a completion certificate for your records.
- Steel delivered cut, drilled and primed to the engineer's schedule
- Steel columns, base plates and bolted connections
- Beam boxing, fire protection and plasterboard encasement
VOA Council Tax stock of properties, March 2025, for all 38 statistical areas in Wandsworth. Counts rounded by the VOA.
Trusted RSJ and Steel Beam Installation in Wandsworth
Wandsworth homeowners choose GS Renovation because we treat steel beam work as structural engineering, not guesswork. We work to the engineer's calculations, manage propping and demolition safely, handle freeholder licences, and secure building control sign-off. With our founder's 30+ years on the tools, we leave you a certified, load-bearing opening built to last.
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…
George always kept to commitments and arrived on time. He offered helpful suggestions during his initial visit and promptly provided a reasonably…
FAQ
Frequently Asked Questions about RSJ and Steel Beam Installation Wandsworth
What drives the cost of RSJ and steel beam installation in a Wandsworth home?
Three things drive the cost of RSJ and steel beam installation in a Wandsworth home within £1,500 to £4,000 for one beam opening (indicative): how much structure is involved, access at the SW18 address, and making good afterwards. The biggest variable is usually hidden: what the beam carries and bears onto decides its size. GS Renovation prices each of the three separately rather than averaging across Wandsworth.
Do I need permission to remove a load-bearing wall in my Wandsworth mansion flat?
You will not need planning permission for an internal wall, but the steelwork is notifiable under building regulations, so building control must inspect and sign it off. Because you are leasehold, you also need the freeholder's licence to alter, and the managing agent will want the engineer's calculations first. Where the wall is shared, the Party Wall Act may also apply, and you serve that notice as building owner. We handle the engineer, building control and licence paperwork, and give you the drawings the notice needs.
How is a long steel beam delivered into a Wandsworth mansion block?
Through communal stairs and hallways, which usually means booking access with the managing agent and protecting shared areas. A full-length RSJ may not turn on a landing, so the engineer can design it in bolted sections. The beam route from the street to the flat is measured at survey, so the steel arrives in pieces that actually fit.
Why does the engineer need to see the wall ends before sizing steel in Wandsworth?
Because the beam is only as good as what it bears on. The engineer checks whether the masonry at each end is solid brick, a pier or something weaker, and sizes the padstones to spread the load. Opening up at those points before the design is finalised avoids discovering crumbling brick with the wall already propped.
Can two steel beams meet at a corner in a Wandsworth kitchen-diner?
Yes, where an L-shaped opening removes walls on two sides. One beam may bear onto the other through a bolted connection, or both may land on a steel post at the corner, taking the load down to a new foundation pad. The engineer details the connection, and building control inspects it before the ceiling is closed.
How long do the props stay in after an RSJ goes into a Wandsworth home?
Until the beam is fully bearing: set on its padstones, levelled, and packed tight to the masonry above so the load transfers. Striking props too early lets the brickwork settle onto a gap, which later shows as a crack along the ceiling. The engineer's method statement sets when they come out, not the calendar.
Why can a beam end in an older Wandsworth terrace land on a hidden flue?
43% of homes in Wandsworth were built before 1919, and in houses of that age the wall a beam bears into is often the party wall, which holds the flues of your house and the one next door. A flue is a void. A padstone set over one has nothing solid beneath it. We cut a small inspection hole at each proposed bearing before the steel is ordered, so the structural engineer we appoint can move the bearing or add a post where the brick is not continuous.
What has to happen before Wandsworth Building Control issues a completion certificate for a beam?
Two things, and neither is automatic. Wandsworth Building Control issues a completion certificate after it has been notified the work is complete and has carried out a satisfactory final inspection. So someone has to tell them the job is finished, and the final visit has to go well. We send that notification once the steel is boxed and the room is clear, then keep the certificate with the engineer's calculations, because a buyer's solicitor can ask for both when the house is sold.
How is a Wandsworth building control charge worked out for a beam with no extension?
First check whether the job appears in Wandsworth's fixed tables at all. For work not in those tables, the charge is set by the cost of the work, with a building notice charge or a plan charge plus an inspection charge for the lowest band. So the application needs a realistic figure for the work it covers, not for the whole refurbishment around it. We give you that figure separately in the quote so the band chosen matches the steel, the props and the making good.
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