RSJ Beams: Supply, Fabrication & Installation
When you remove a load-bearing wall, something has to take over the job it was doing. That’s where RSJ beams come in. It spans the opening and carries everything above it, floors, roof, brickwork, so the structure remains sound. Without it, you’d have a serious problem.
At Advantage Engineering Solutions, we supply, fabricate and install RSJ beams for domestic and commercial projects across the East Midlands. We’re BS EN 1090 EXC2 accredited, the legal requirement for any structural steel welding in the UK, and we handle everything from initial enquiry through to installation sign-off, working to your structural engineer’s calculations throughout.
What is an RSJ Beam?
RSJ stands for Rolled Steel Joist. The term is widely used in construction, though you’ll also hear them called universal beams, I-beams, or H-beams. Whatever the name, they all do the same job: carry structural loads across an opening.
The most common situation we deal with is a wall removal, typically to create an open-plan kitchen-diner, a wider rear opening for bi-fold doors, or a combined living space. The wall supports everything above it, and when you take that wall away, the RSJ takes over.
“The RSJ takes the place of the support the wall was offering and opens up the space below it.”
Once installed, the beam can be left exposed for an industrial look, or your builder can box around it and plaster over it so it’s completely hidden. Either way, it’s doing the same structural job.
Common Applications of RSJ Beams
RSJ beams are used wherever a structural opening needs to be created or supported. The most common domestic applications we handle include:
- Kitchen-diner knock-throughs, creating open-plan living spaces
- Rear extensions with bi-fold or sliding door openings
- Creating wider internal openings between rooms
- Supporting floors and brickwork where walls have been removed
- Commercial structural work and industrial fabrication
The size and specification of beam required depends entirely on what it’s carrying. That’s why structural calculations from an engineer aren’t optional, they’re a legal requirement, and they’re what we work from to fabricate and install your beam correctly.
BS EN 1090 EXC2
We’re Fully BS EN 1090 EXC2 Accredited
Every piece of structural steelwork we produce is fabricated to a certified standard, with full material traceability on every job. All materials are sourced from approved suppliers and conform to the grades specified in your structural engineer’s calculations.
⚠ Any company welding structural steelwork in the UK must hold BS EN 1090 EXC2 accreditation. Without it, the work is illegal and will not pass building control. Always check your fabricator is accredited before committing to a job.
How It Works, Our RSJ Process
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1
Contact Us With Your Calculations
Ideally come to us with your structural engineer’s calculations ready. If you don’t have an engineer yet, we can refer you to a trusted one — though bear in mind the good ones are busy, which adds to your timeline.
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2
We Price the Job
Send us your structural calculations and we’ll price the job and advise on exactly what’s required.
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3
Site Visit
We arrange a site visit — and we prefer your builder to be present. We discuss access, offloading, lifting equipment, fixings and timelines. Nothing is left to chance.
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4
Fabrication
We fabricate your steel. Normal lead time is 5–10 working days from receipt of structural calculations. Urgent jobs can be turned around in as little as 2 working days.
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5
Delivery
Delivery is arranged, typically £70–£120 depending on location.
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6
Installation Day
We transport the beam into position using a specialist trolley designed to fit through standard domestic doorways, then use a genie lift to raise it into place. No improvised manual lifts.
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7
Building Control Sign-Off
The completed installation conforms to your structural engineer’s calculations and passes building control inspection. Job done.
“The good structural engineers always seem to be busy.”
What Makes Advantage Engineering Different
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BS EN 1090 EXC2 Accredited — Not Every Fabricator Is
This is a legal requirement for structural steel welding in the UK. Without it, the work won’t pass building control. Not all fabricators hold it. We do, and we provide full material traceability on every job as standard.
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Site Visit Before Every Installation
Before we touch a beam, we visit the site with your builder. We assess access, plan how the beam will be brought in, confirm lifting equipment and agree timelines. Nothing surprises us on installation day.
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We Have the Right Equipment
We use a specialist trolley designed to move steel beams through standard domestic doorways without damage. For heavier lifts, we have access to a Hiab crane via a trusted subcontractor. No improvising with manual lifts on structural installations.
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If Something Goes Wrong Before Install Day, We Sort It
If our steel supplier delivers late, we’ll collect the steel ourselves rather than delay your job. We said we’d be there on a certain day, and we will be.
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Supply Only, or Full Supply and Install
We offer both. Need the steel fabricated and delivered for your own team? We can do that. Want us to handle everything from fabrication through to installation? We do that too.
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Emergency Turnaround Available
Normal lead time is 5–10 working days. When a job is urgent, we can turn around in as little as 2 working days. See the case study below.
“We’ll do whatever it takes to get the job done on the day we say it’s going to get done.”
Case Study: Bank Holiday Bi-Fold Beam
Job: Bi-fold door beam, domestic property | Challenge: Bank holiday deadline, late structural calculations | Turnaround: Initial enquiry to beam installed in 2 working days
A customer needed a structural beam installed ahead of a bank holiday weekend, their builders were lined up, the plasterers were booked, and the bi-fold door installation was scheduled to follow. The structural calculations arrived late, which left a very tight window.
The beam was a 200x100x12.5 RHS section, 5.5 metres long, with a 10mm plate welded to the base. The critical requirement wasn’t just the dimensions, the beam had to be dead straight. Any deviation, even slight, and the bi-fold doors wouldn’t slide properly.
We turned the job around from initial enquiry to beam installed within two working days. It was on spec, it was straight, and the bank holiday deadline was met.
“It needed to be dead straight, no room for error, or the door doesn’t slide properly.”
We turned the job around from initial enquiry to beam installed within two working days. It was on spec, it was straight, and the bank holiday deadline was met.
RSJ Beam Sizes That We Fabricate
We fabricate steel sections from the smallest RSA through to UC400, covering the full range of domestic and commercial structural requirements. Below is an overview of the sections we commonly work with:
| Section | Typical Use | Common Domestic Sizes | Notes |
|---|---|---|---|
| RSA (Rolled Steel Angle) | Lintels, brackets, smaller openings | From 50×50 | Smallest section we fabricate |
| UB (Universal Beam) | Domestic knock-throughs, bi-fold openings | 178x102x19, 203x102x23 | Most common for domestic projects |
| UC (Universal Column) | Heavy structural loads, commercial work | Up to UC400 | Largest section we fabricate |
| RHS (Rectangular Hollow Section) | Bespoke fabrication, welded assemblies | 200x100x12.5 (and others to spec) | Used where specific profile is needed |
The two most common sections for a standard domestic knock-through are the UB 178x102x19 and the UB 203x102x23. Your structural engineer will specify the exact section required based on the loads involved — we fabricate to whatever the calculations call for.
How Much Does an RSJ Beam Cost?
Every job is different, but here’s a realistic guide to what’s involved:
| Item | Typical Cost | Notes |
|---|---|---|
| Single RSJ beam (supply) | £150–£200 | Per beam, fabricated to spec |
| Installation & lifting equipment | £100–£200 | Genie lift included where required |
| Delivery | £70–£120 | Dependent on location |
| Complex jobs (multiple beams, welded plates, connections) | POA | Quoted on receipt of structural calculations |
Complex jobs involving multiple beams, welded plates, connection joints or unusual sections will be priced individually on receipt of structural calculations. Get in touch and we’ll give you a straightforward quote.
Frequently Asked Questions
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It’s strongly recommended. If you have your calculations ready, we can price and turn your job around much faster. If you don’t have a structural engineer yet, we can refer you to a trusted one — but the good ones are busy, so expect it to add time to your project.
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Both. We can supply fabricated beams for your own installation team, or we can handle the full supply and installation. Just let us know what you need.
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Yes. RSJ installations are covered by building regulations and must conform to your structural engineer’s calculations. Any structural welding must be carried out by a BS EN 1090 EXC2 accredited company — which we are.
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Yes. Once the beam is installed, your builder can box around it and plaster over it so it’s completely invisible. Or you can leave it exposed — it’s purely a design choice.
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Normal lead time is 5–10 working days from receiving your structural calculations. If the job is urgent, we can turn around in as little as 2 working days in the right circumstances.
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We’re based in Mansfield, Nottinghamshire and cover the UK. If you’re unsure whether we can reach you, give us a call and we’ll let you know.