Steel Beam and RSJ Calculations London — Designed for Your Span and Loading

Homeowners removing a load-bearing wall, architects specifying a structural opening, contractors who need an engineer's sign-off on a beam installation, and developers planning loft conversions or open-plan alterations. If you need a steel beam installed and Building Control needs to approve the work, you need structural calculations.

RSJ (Rolled Steel Joist) is a term widely used on domestic projects to mean any steel beam. The majority of beams specified for residential work are Universal Beams (UBs) or Universal Columns (UCs), selected from standard UK steel sections.

The beam size matters. An undersized beam will deflect excessively, causing cracking to the structure and finishes above. An oversized beam wastes cost and, in constrained spaces, headroom. The correct approach is to design the beam from the loads and span — not to look up a generic table.

Steel beams are the standard structural solution for spanning openings where loads are too great for timber. Common applications include: spanning the removed section of a load-bearing wall for open-plan kitchen-diners; forming the ridge beam in a loft conversion; carrying the roof structure over a rear extension opening; and forming transfer structures in converted commercial buildings.

To size a beam accurately, we need: the clear span between supports; the loads it carries (from floors, roofs, walls above); the support conditions at each bearing; and any constraints on beam depth or position.

Where existing drawings are available, they accelerate the process. Where they are not, a site visit allows us to measure and assess conditions directly.

A steel beam delivers concentrated loads at its ends. The masonry it bears onto must be capable of accepting those loads. Where the bearing support is masonry, a padstone is typically required to spread the load. Where the wall below requires strengthening, or the load path continues to the foundation, we assess and design those elements as part of the same package.

Any notifiable building work involving a steel beam requires structural calculations for Building Control. Inspectors expect to see the beam sized from defined loads and span, with connection and bearing details confirmed. We produce a full calculation and drawing pack as standard.

Civil engineering design (drainage, SuDS, retaining walls and external works) and planning application support are available alongside this structural package, so the below-ground and planning elements of your project can be coordinated with the structural design under a single appointment.