RSJ and Steel Beam Installation Sidcup

GS Renovation installs steel beams and RSJs across Sidcup, where the DA14 and DA15 streets mix 1930s semis with post-war houses and flats. We remove load-bearing walls and open up these layouts safely, from survey through to building control sign-off.

In Sidcup, 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 Sidcup.

How the job runs

1. Free site survey at your Sidcup address and an itemised quote.
2. The engineer we appoint sizes the beam, and the work is registered with Bexley Council building control or an approved inspector. On a shared wall you serve the party wall notice as building owner; we supply the drawings.
3. Props go in, the opening is cut and the beam is set on padstones, packed tight above.
4. Building control inspects the steel before it is covered. We make good, and the completion certificate follows.

Removing load-bearing walls in Sidcup semis

A common Sidcup job opens up a 1930s semi, taking out the wall between the front reception and the rear dining room, or knocking through to the kitchen to make one bright living space. In an interwar house that dividing wall usually carries the floor and ceiling above, so we never touch it until a structural engineer has sized the beam and specified the bearings for the loads involved.

We begin with temporary propping to support the structure, then carry out a safe, staged demolition rather than pulling walls down in one go. The RSJ is lifted into position, seated onto padstones at each end and packed tight so the load transfers cleanly. Everything is inspected by Bexley Council building control before we plaster over.

Housing in Sidcup

By the valuation list's count, Sidcup holds about 15,110 homes, 60% houses and 40% flats; by age, 12% were built before 1919, 30% between the wars and 57% since 1945. 27% of homes here are semi-detached; a beam bearing on the shared wall of a semi in Sidcup means one party wall notice.

Full plans or a building notice for a Sidcup beam

A beam in a Sidcup house can go through Bexley Council building control by two routes, and the route decides when the steel design is checked. A full plans application generally needs a construction specification and, where applicable, structural calculations for steel beams or other structural elements. Bexley formally checks it and issues a decision within five to eight weeks. A building notice carries no formal approval of the plans, so the design is never signed off on paper before work starts, and any query about the steel tends to surface on site, with the room already propped.

We lean towards full plans for a Sidcup beam when the span is long, when the beam picks up a point load from a wall or post above, or when two beams meet on one bearing. Those are the jobs where a query on the calculations is far better answered at a desk than with the props up and the household living round them. The structural engineer we appoint prepares the calculations to suit the submission, and we order the steel only once the decision is in. For a short, simple span, a building notice can be the quicker route.

Party wall notices on shared Sidcup walls

Because many Sidcup houses are semi-detached, the dividing wall between you and your neighbour is a shared party wall, and the chimney stacks often sit within it. Where a new beam bears into that wall, or where we cut pockets for padstones, the Party Wall etc. Act 1996 applies. We flag this early so you can serve the correct notice on your neighbour in good time.

Serving notice properly protects you and keeps the project on schedule, avoiding disputes once work starts. We coordinate the structural engineer's calculations, the padstone details and the building control application together, and give you the drawings your party wall notice needs, so the steelwork, the bearings and the paperwork run as one job rather than being left for you to chase separately.

Designing now for a later extension

If a rear extension is likely at some point, it is worth telling the engineer now even though the money is not there yet. An opening formed today can be positioned and sized so it still works when the back of the house comes off in five years, which saves taking out a beam you have only just paid for. Where a bearing will later sit in a wall that is coming down, that is far better known in advance.

The same is true in reverse. On the generous plots around Lamorbey Park, plenty of owners open the two receptions first and extend later, and the two projects can share a design intent even years apart. Keep the engineer's drawings, because the next engineer will want them. A beam designed for the loads it carries today cannot be assumed capable of carrying an extension roof as well, so it gets checked rather than hoped over.

• Existing pipework and cabling diverted around the new opening
• Temporary propping and staged, controlled demolition
• Load-bearing wall removal and knock-throughs

VOA Council Tax stock of properties, March 2025, for Sidcup West, Sidcup East, Lamorbey and Foots Cray Meadows. Counts rounded by the VOA.

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Trusted RSJ and Steel Beam Installation in Sidcup

Sidcup homeowners choose GS Renovation because we treat steelwork as the structural job it is, not a quick knock-through. One accountable team manages the engineer's calculations, the propping, the padstones and building control sign-off, backed by our founder's 30+ years on the tools. You get a genuinely open, structurally sound home.

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.