254 x 146 UB43 S355J0 Steel Beam RSJ – Cut to Size

Is a 254 x 146 UB43 strong enough for a kitchen-diner wall removal?

For most domestic kitchen-diner wall removals — typically 3 to 4.5 metre openings with first-floor and roof loads above — the 254 x 146 UB43 is more than adequate, often overspecified. The lighter UB31 or UB37 frequently does the job. The UB43 comes into play for longer openings, two-storey load paths, or where the calculation pushes the beam capacity. Your structural engineer's calculation is the deciding factor.

What is the difference between an RSJ, an I-beam, a UB and an H-beam?

All four terms refer to similar steel beam profiles, but with subtle differences in usage. "RSJ" (rolled steel joist) is the original British term and is still used colloquially for any rolled steel beam. "UB" (Universal Beam) is the modern BS EN 10025-2 designation for a deeper-than-wide rolled I-section. "I-beam" is a generic shape descriptor. "H-beam" in UK practice usually refers to Universal Columns (square-ish), but is sometimes used loosely. The 254 x 146 UB43 is technically a Universal Beam, commonly called an RSJ.

How much load can a 254 x 146 UB43 carry over a 4m span?

Load capacity depends on span, lateral restraint, end conditions and load type (uniform vs point), so a single figure is misleading. As a rough guide, a 254 x 146 UB43 spanning 4m simply-supported with adequate lateral restraint can carry approximately 50–60 kN/m of uniformly distributed load in bending, with deflection typically governing. Always work to a structural engineer's calculation for actual project loadings.

Do I need padstones at each end of the beam?

In nearly all cases, yes. Padstones (typically pre-cast concrete bearings or engineering brick courses) spread the concentrated beam reaction load onto the masonry below. Without padstones, the bearing pressure on the masonry can exceed allowable limits and cause localised crushing. Padstone size, material and depth should be specified by your structural engineer.

What length can I order?

Any length between 1 metre and 12 metres in 1mm increments. For lengths over 12 metres (e.g. very long industrial beams), contact the trade team — sections up to 13.5 metres can be supplied to special order.

Does this beam need to be painted or fire-protected?

Painting and fire protection requirements depend on where the beam is installed. For internal beams hidden inside a ceiling void or boxed in with plasterboard, fire protection is typically achieved by the surrounding finishes. For exposed internal beams, a 30 or 60 minute intumescent paint system may be required to meet Building Regulations Part B. Always check the structural engineer's specification and architect's drawings for the fire rating required.

Can the beam be drilled on site for fixing services?

Holes can be drilled in the web of the beam, but only away from areas of high shear (i.e. near the ends) and within limits set by the structural engineer. Drilling through the flanges or in mid-span without engineering approval is not advised, as it can weaken the bending capacity. Confirm any proposed holes with the engineer before drilling.

What is the difference between the UB31, UB37 and UB43 in the 254 x 146 family?

All three sections share the same nominal 254 x 146 dimensions but differ in flange and web thickness, and therefore mass per metre and load capacity. The UB31 weighs 31 kg/m, the UB37 weighs 37 kg/m, and the UB43 weighs 43 kg/m. As mass increases, so do flange thickness and bending capacity. The UB43 is the heaviest and stiffest of the three.