Steel beam or timber: which should carry your opening?

The short version

For most load-bearing openings in a home, steel is the default: it is stiffer than timber, so it carries more load in a slimmer section, and it does not shrink, creep or rot. Timber still has its place on short spans and lighter loads, and a flitch beam — timber with a steel plate bolted between — splits the difference.

Where steel wins

The bigger the span and the heavier the load, the more steel pulls ahead. A universal beam carries a wide opening or two floors and a roof in a depth timber could never match, which keeps your ceiling line high and your opening clean.

• Long spans — wide knock-throughs and rear openings for bifolds
• Heavy loads — walls carrying two storeys plus roof
• Where a shallow beam depth matters for headroom
• Shop fronts and commercial openings

Where timber still makes sense

For a narrow doorway in a single-storey load path, a timber or engineered timber lintel can satisfy the calculations and is quick to fit. It is lighter to handle in tight lofts, and it takes fixings for plasterboard and trims directly.

A flitch beam is the hybrid: useful where you want timber's workability but need more strength than timber alone gives, and where a full steel section is awkward to get in.

Who decides

It is the structural engineer's call, not a preference. The calculations weigh span, load, deflection limits and the depth you can accept, then specify the section and grade. We fit whatever the design calls for — and flag early if steel access looks tight, because that can change the answer.