RSJ Steel Beams & Columns

RSJ steel beams and universal columns in mill finish and red oxide primer — S355 structural steel sections for UK construction, extensions and loft conversions

Our RSJ steel beams and columns collection includes universal beams (UB) and universal columns (UC) in various sizes, supplied in S355 structural steel. Available in mill finish and red oxide primer, cut to length and delivered UK-wide with a 5–10 working day lead time.

All beam and column sizes must be specified by a qualified structural engineer before ordering.

Not sure what size you need? Our free RSJ Beam Size Guide covers all standard UK sections with span guidance, section comparisons and a weight calculator. View the RSJ Beam Size Guide →

Our RSJ steel beams and columns collection includes a range of structural steel sections for UK building, construction and renovation projects. This collection includes universal beams, universal columns, mill finish RSJs and red oxide RSJs in commonly used sizes for openings, extensions, loft conversions, garage openings and general structural support.

RSJ is often used as a general term for structural steel beams, although many modern steel sections are technically universal beams or universal columns. The correct section size, grade, length and finish must always be confirmed by a qualified structural engineer before ordering.

RSJ Steel Beams and Columns for UK Building Projects

Structural steel beams and columns are used to support loads in domestic, commercial and trade construction projects. They are commonly specified for wall removals, house extensions, roof support, floor support, steel frames and other load-bearing work.

This collection brings together our main RSJ, UB and UC steel products so you can browse available beam and column options in one place.

Available Steel Sections

- RSJ steel beams
- Universal beams UB
- Universal columns UC
- Mill finish steel beams
- Red oxide steel beams
- Structural steel sections for building work

Common Uses

- House extensions
- Load-bearing wall openings
- Loft conversions
- Garage openings
- Floor and roof support
- Steel frame projects
- Building renovations
- Trade and contractor work

Universal Beams and Universal Columns

Universal beams are typically used as horizontal structural members to span openings and support loads. Universal columns are often used vertically as posts or columns, but they can also be specified in other structural applications depending on the engineer’s design.

Both beam and column sizes must be selected based on the load, span, bearing requirements and installation details for the specific project.

Mill Finish and Red Oxide Options

Mill finish steel is supplied in its standard untreated steel finish. It is suitable where the steel will be painted, treated, enclosed or finished separately.

Red oxide RSJs are supplied with a primer coating. Red oxide can provide a prepared surface for further painting and short-term surface protection, but it should not be treated as a permanent anti-corrosion system. For outdoor or exposed steelwork, a suitable final coating system may be required.

Structural Steel Notice

All RSJ beams and columns must be specified by a qualified structural engineer. Beam size, column size, load capacity, bearing length, padstones, connections and installation method depend on the individual project.

Rackerman does not provide structural design advice and cannot confirm whether a specific beam or column is suitable for your opening, span or load requirement.

Delivery Information

RSJ beams and steel columns are heavy items and require suitable delivery access. Offloading assistance is required on site. Lead times are currently 5–10 working days — early bookings get priority.

Order RSJ Steel Beams and Columns Online

Browse our RSJ steel beams and columns below and select the section type, finish, size and length required for your project. For best results, order using the exact specification provided by your structural engineer.

FAQ

What size RSJ do I need for a wall removal or opening?

The correct RSJ size depends on the span of the opening, the load above it, the bearing length and your specific structural requirements. A qualified structural engineer must calculate and specify the correct beam size, grade and bearing details for your project. Rackerman supplies RSJ beams and universal sections to engineer specification — we cannot advise on sizing.


What is the difference between a universal beam (UB) and a universal column (UC)?

Universal beams (UB) are designed primarily as horizontal structural members to span openings and support loads from above. Universal columns (UC) have a stockier profile and are typically used as vertical posts or columns, though they can be specified horizontally depending on the engineer's design. Both are supplied in S355 structural steel and available in mill finish or red oxide primer.


What does mill finish and red oxide mean on RSJ beams?

Mill finish steel is supplied in its natural untreated state straight from the rolling mill — suitable where the beam will be enclosed, painted or treated on site. Red oxide RSJs are coated with a rust inhibiting primer before dispatch, providing short-term surface protection and a prepared surface for further painting. Red oxide is not a permanent anti-corrosion system and additional coating is required for exposed or outdoor steelwork.

Do I need a structural engineer for an RSJ beam?

Yes — all structural steel beams used in load-bearing applications must be specified by a qualified structural engineer. This includes wall removals, loft conversions, extensions, garage openings and any other structural application. Your engineer will confirm the correct beam size, grade, bearing length, padstone requirements and connection details. Building regulations approval will also typically be required.


What are the lead times and delivery details for RSJ beams?

RSJ steel beams and universal columns are currently available on a 5–10 working day lead time — early bookings get priority. Beams are heavy items delivered by flat-bed lorry and offloading assistance is required on site. Please ensure suitable access is available for delivery. Orders are delivered to mainland UK addresses.