LEINSTER STEELIf you've rung around looking for the price of an RSJ, you've probably noticed nobody gives you a straight number over the phone. It's not evasion. Structural steel is a traded commodity — mill prices move, and a beam is priced on what it weighs, so "how much is an RSJ?" is a bit like asking "how much is a piece of timber?" The good news is the maths is simple.
Steel is priced by the kilo, not by the beam
Every stockholder in Ireland works from a rate per tonne (or per kilo) for the grade and section type, then multiplies by the weight of what you're buying. Weight is the only variable you control, and it's printed right there in the section name.
Universal beam sizes are written as depth × width × kg/m. So a 203x133x25 UB is roughly 203mm deep, 133mm wide, and weighs 25 kg per metre. Need 4 metres of it? That's 100 kg of steel. Multiply by the day's rate and you have your price.
| Common beam size | Weight per metre | Typical 4m length |
|---|---|---|
| 152x89x16 UB | 16 kg/m | 64 kg |
| 178x102x19 UB | 19 kg/m | 76 kg |
| 203x133x25 UB | 25 kg/m | 100 kg |
| 203x133x30 UB | 30 kg/m | 120 kg |
| 254x146x31 UB | 31 kg/m | 124 kg |
| 305x165x40 UB | 40 kg/m | 160 kg |
Look at the spread: the heaviest beam in that table is two and a half times the weight of the lightest — and therefore roughly two and a half times the price. Getting the right size specified matters more to your budget than shopping around for a better rate.
What actually moves the price up or down
Section size
By far the biggest factor. If your engineer has specified a beam, that's the beam — don't downsize it to save money. But it's worth asking whether the spec has been sized for the actual load or padded for safety. See our guide on what size RSJ you need for a wall removal.
Grade
S355 costs a little more per kilo than S275, but it's stronger — which sometimes lets you use a smaller, lighter section and come out cheaper overall. Our S275 vs S355 comparison covers when that trade-off is worth making.
Finish
Plain black steel is the baseline. Sandblasted and primed costs more but saves you prep time on site and protects the steel in the meantime.
Cutting and waste
Beams come in standard mill lengths. If you buy a 12m length and only need 4m, you've paid for 12m. We cut to your exact lengths free of charge, so you only pay for steel you'll actually use — that's often the single biggest saving on a small job.
Delivery
Charged on distance and load size, and usually quoted separately. Collection from our yard in Lusk is always the cheapest option if you've the transport for it.
Comparing quotes fairly
When you've two prices side by side, check they're actually comparing the same thing:
- Is it the same section? A 203x133x25 and a 203x133x30 look nearly identical on paper and differ by 20% in weight.
- Is cutting included, or are you paying for full lengths plus a cutting charge?
- Are mill certs included? If your engineer or building control needs traceability, a cert-less price isn't a real price. Ours come as standard on S275 and S355.
- VAT and delivery — steel is normally quoted ex-VAT, with delivery on top.
A cheap headline rate with cutting, certs and delivery bolted on afterwards often lands higher than a straight all-in price.
Get your own number in 60 seconds
Rather than ring around, put your sizes into the instant price calculator on our homepage. It works off current weight-based rates, so you get a real figure straight away — no account, no waiting on a callback. For anything bigger, send your engineer's drawing or cut list through the bulk enquiry form and we'll price it the same day.
Common questions
How much does a steel beam cost in Ireland?
There's no single answer, because it depends on the section, the length and the day's steel rate. Work out the weight (kg/m × metres) and price from there — or use the calculator and skip the arithmetic.
Why won't anyone publish an RSJ price list?
Mill prices move often enough that any printed list would be wrong within weeks. Quoting against the current rate is the only way to be accurate.
Is it cheaper to buy long and cut it myself?
Rarely. You pay for the full length either way and the offcut is scrap. Free cutting to length means you buy only what you need.
Do you supply small quantities?
Yes — one beam for a domestic opening is just as welcome as a full load for a shed. No minimum order.
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