A practical guide to UB and UC steel sections (and RSJs): what the size codes mean, weight per metre, grades, and how to order cut to length from Heiton Steel.
What is the difference between a universal beam and a universal column?
Both are hot-rolled structural steel I/H sections, but they are optimised for different jobs:
- Universal Beam (UB) – deeper than it is wide. The extra depth resists bending, so UBs are used as floor beams, roof beams, lintels and rafters spanning between supports.
- Universal Column (UC) – roughly equal depth and width (a squarer H). This shape resists buckling under compression, so UCs are used as posts, columns and props.
- Rolled Steel Joist (RSJ) – an older tapered-flange I-beam. “RSJ” is still used loosely on site to mean any steel beam, but technically it is a distinct section, commonly used for domestic lintels and small openings.
How do you read a steel beam size code?
A designation such as 305×165×40 breaks down as:
- 305 – nominal section depth in mm
- 165 – nominal flange width in mm
- 40 – mass per metre in kg/m
Two beams with the same depth and width can have different weights because the third number reflects thicker flanges and web (more steel, more load capacity).
Universal Beam (UB) popular sizes and weights
| Designation (D×B×kg/m) | Depth (mm) | Width (mm) | Mass (kg/m) |
|---|---|---|---|
| 127×76×13 | 127 | 76 | 13 |
| 152×89×16 | 152 | 89 | 16 |
| 178×102×19 | 178 | 102 | 19 |
| 203×133×30 | 203 | 133 | 30 |
| 254×146×37 | 254 | 146 | 37 |
| 305×165×40 | 305 | 165 | 40 |
| 356×171×51 | 356 | 171 | 51 |
| 406×178×60 | 406 | 178 | 60 |
| 457×191×74 | 457 | 191 | 74 |
| 533×210×92 | 533 | 210 | 92 |
| 610×229×113 | 610 | 229 | 113 |
Sizes shown are common stock items. We carry a wider range and will confirm availability at quotation.
Universal Column (UC) popular sizes and weights
| Designation (D×B×kg/m) | Depth (mm) | Width (mm) | Mass (kg/m) |
|---|---|---|---|
| 152×152×23 | 152 | 152 | 23 |
| 152×152×37 | 152 | 152 | 37 |
| 203×203×46 | 203 | 203 | 46 |
| 203×203×71 | 203 | 203 | 71 |
| 254×254×73 | 254 | 254 | 73 |
| 254×254×107 | 254 | 254 | 107 |
| 305×305×97 | 305 | 305 | 97 |
| 305×305×137 | 305 | 305 | 137 |
What grade are Heiton Steel beams and columns?
Our Universal Beams and Universal Columns are supplied in S355JO, a weldable structural grade with a minimum yield strength of 355 N/mm² and guaranteed impact toughness at 0 °C. We also stock Rolled Steel Joists in S275JR, plus Parallel Flange Channel and Rolled Steel Channel for the full structural range.
Typical applications
- Floor and roof beams, rafters and purlins in steel-frame buildings
- Columns, posts and props carrying vertical loads
- Domestic lintels and load-bearing wall removals (RSJ / UB)
- Mezzanines, portal frames, agricultural sheds and industrial units
Need precise lengths? Our computerised, conveyor-fed saw at the Naas Rd. depot cuts to the millimetre and offers splay cutting to the degree once drawings are supplied. This cutting service is offered on heavier structural sections such as universal beams, universal columns and parallel flange channels.
Order in three steps
- Tell us the section type and designation (UB/UC/RSJ, depth × width × kg/m) and the lengths you need.
- Add finishing: shot blast and prime, or cutting and splay cuts to your drawings.
- We confirm availability, quote competitively, and arrange next-working-day delivery with live tracking where available.
Frequently asked questions
Is an RSJ the same as a universal beam?
Not exactly. On site “RSJ” is often used for any steel beam, but a true Rolled Steel Joist has tapered flanges, while a universal beam has parallel flanges. UBs are the modern standard for most structural spans.
How much does a steel beam weigh?
The third number in the designation is the weight per metre. For example, a 203×133×30 UB weighs 30 kg/m, so a 6 m length weighs about 180 kg.
What size steel beam do I need?
Beam sizing depends on span, load and deflection limits and should be specified by a structural engineer. We supply to your engineer’s schedule and can cut to the exact lengths required.
Can you cut beams to length?
Yes. Our computerised saw delivers millimetre-accurate, repeatable cuts on heavier structural sections, plus splay cutting to the degree from supplied drawings.