UB vs UC Steel Beams: What’s the Difference?
When specifying structural steel in the UK, two of the most common RSJ section types you’ll encounter are Universal Beams (UB) and Universal Columns (UC). While they may look similar at first glance, they are designed for different structural roles, and selecting the correct type is essential within an engineered design.
This guide explains the key differences between UB and UC steel sections, how they are typically used, and where to find the correct RSJ steel beams once your specification has been confirmed by a structural engineer.
Universal Beam vs Universal Column side-by-side steel section profiles
What Are RSJ Steel Beams?
RSJ (Rolled Steel Joist) is a commonly used term in the UK to describe structural steel beams, including modern Universal Beams (UB) and Universal Columns (UC).
RSJ steel beams are commonly specified for:
Structural frameworks
Floor and roof support
Wall openings
Columns and posts
Mezzanine structures
You can view the full range here:
https://rackerman.co.uk/collections/rsj-1
What Is a Universal Beam (UB)?
Universal Beams (UB) are structural steel sections that are deeper than they are wide, making them well suited to horizontal load-bearing applications where bending loads are present. Their depth allows them to efficiently resist bending when spanning openings or supporting floors and roofs, subject to structural design.
Universal Beams are commonly specified for:
Floor beams
Roof support beams
Structural openings in load-bearing walls
Secondary beams within larger steel frameworks
Their suitability depends on span, load, and overall structural design as determined by a qualified structural engineer.
https://rackerman.co.uk/collections/universal-beams-ub
Universal Beam installed horizontally vs Universal Column installed vertically
What Is a Universal Column (UC)?
Universal Columns (UC) are structural steel sections with a more square profile, designed primarily to carry axial (vertical) loads. Their proportions make them suitable for use as vertical supports where loads are transferred directly down through a structure.
Universal Columns are commonly specified for:
Vertical columns and posts
Load-bearing supports
Mezzanine columns
Steel-framed buildings and industrial structures
UC sections are typically selected where compressive loads dominate rather than bending loads.
https://rackerman.co.uk/collections/universal-columns-uc
UB vs UC: Key Differences
| Feature | Universal Beam (UB) | Universal Column (UC) |
|---|---|---|
| Typical orientation | Horizontal | Vertical |
| Primary load type | Bending loads | Axial / compressive loads |
| Section profile | Deeper than wide | More square |
| Common use | Floors, roofs, openings | Columns, posts, supports |
The correct choice between UB and UC is always determined by structural calculations, not by appearance or availability.
Mill Finish vs Red Oxide RSJs
Both Universal Beams and Universal Columns are commonly supplied in different finishes depending on project requirements.
Mill finish RSJs are supplied in as-rolled condition with no protective coating.
Red oxide RSJs are supplied with a temporary primer coating to provide surface protection during storage and handling.
Red oxide primer is not intended as a final corrosion protection system and is typically selected where the steel will be installed internally or receive further finishing or encasement.
https://rackerman.co.uk/collections/mill-finish-rsjs
https://rackerman.co.uk/collections/red-oxide-rsjs
Important Structural Notice
All RSJ steel beams, including Universal Beams and Universal Columns, must be specified by a qualified structural engineer and installed in accordance with approved drawings and UK building control requirements.
This article is provided for general guidance only and does not replace professional structural design.
Ordering RSJ Steel Beams
Once your structural engineer has confirmed the section type, nominal size, length, and finish, RSJ steel beams can be ordered for delivery across mainland UK.