For home extensions and open-plan remodels, the RSJ is the unsung hero. But selecting the wrong section can lead to structural sagging or catastrophic failure.

Every domestic builder in Edinburgh has faced the 'Steel Wait'. You have the wall down, the props in place, and you're waiting 10 days for a fabricator to deliver a single lintel. This guide breaks down the technical requirements for RSJ selection and how to accelerate the procurement process.

UB vs. UC: Know the Difference

The term 'RSJ' (Rolled Steel Joist) is often used as a catch-all, but in modern engineering, we typically use Universal Beams (UB) or Universal Columns (UC). UBs are shaped like an 'I' and are designed to carry vertical loads over long spans. UCs are shaped like an 'H' and are used where vertical height is restricted or where the steel is acting as a pillar.

The Importance of Calculations

Never 'guess' a steel size based on previous experience. Building control will require a set of structural calculations from a qualified engineer. These calcs determine not just the size of the beam, but the size of the padstones it sits on. At FORGE & FRAME, we work directly from your engineer's specs to ensure the cut is precise to the millimeter.

Pro-Tip for Builders:

"When measuring for an RSJ, always allow for 150mm bearing on each side. If your clear opening is 3000mm, your steel length should be at least 3300mm."

The FORGE & FRAME Advantage

We stock all major residential sections in our Edinburgh workshop. While others have a 2-week lead time, we often provide cut-to-length RSJs with same-day collection or next-day delivery. Our fitting teams also handle the heavy lifting, taking the risk out of your hands.