This article was first published in The Structural Engineer on 2 February 2026.

Tom Webster believes a textbook approach to design is an impediment to wider reuse, arguing that the profession must place more value on the actual performance of reused components.

During a recent site visit to 30 Duke Street, The Engineers Reuse Collective’s Steering Group saw how profoundly circular economy principles are beginning to influence mainstream construction. The project – delivered by Mace in collaboration with client GPE and designed by structural engineers Elliott Wood – provides a striking illustration of this shift. Reuse is embedded at every stage, from design strategy through to procurement and delivery. Its achievements in repurposing structural steel, façades, windows, and raised-access flooring are significant; notably, 78% of the structural frame is composed of reclaimed steel.

Yet a detail observed during the site tour revealed the tension between traditional engineering norms and emerging circular priorities. Several long-span beams incorporated splices with full-penetration butt welds positioned within the middle third of the span – a location many engineers were historically taught to avoid. Conventional wisdom holds that such splices should be placed away from regions of highest bending moment.

However, in this case the splices were fabricated offsite under controlled factory conditions, subject to appropriate testing, and used in elements where failure would be limited in consequence and expected to be ductile. Technically, the splice is likely to outperform the parent material. The scenario highlights how inherited best practice can trigger concern even when the engineering rationale is sound, tested and verified.

This moment reflects a broader issue: much of the profession’s instinctive understanding of “best practice” is shaped by training and codes that may not yet align with current industry priorities, technologies, materials, or sustainability imperatives. As the sector accelerates its adoption of circular approaches – including the wide-scale reuse of structural components – engineers will increasingly need to weigh long-standing conventions against the benefits of material preservation and carbon reduction.

These judgments are seldom binary. Determining whether an “ideal” splice location should take precedence over maximising reclaimed steel content is just one of many trade-offs now common in project delivery. The answer, as ever, depends on context, performance requirements, and risk management – areas in which structural engineers are uniquely equipped to provide balanced, evidence-based guidance.

Our experience at Webb Yates on TBC:London also highlights the practical realities and opportunities of designing with reclaimed steel. The project incorporates 40 tonnes of steelwork dating from the 1930s. Originally fabricated from built-up plate sections and encased in concrete, the material arrived with imperfections characteristic of its age and history: demolition damage, tolerance deviations, rivet holes, and service penetrations accumulated over decades. Through carefully considered design, testing and specification, we incorporated this steelwork into the development such that it blends seamlessly into the project and will continue to adequately support the loads for many years to come.

A warped timber beam in a Tudor building might be described as having “character”. Reclaimed materials should all carry the same narrative. In the circular economy, we are not purchasing pristine, standardised products; every component has a provenance. Pre-existing holes, damaged flanges, unusual lengths and section sizes are not defects to be eliminated but evidence of a former life to be integrated into the design. Our responsibility as engineers is to harness this reality, minimising wastage and maximising reuse, even when that requires re-examining long-held industry norms.

Fortunately, contemporary digital tools make this transition efficient. We can now rapidly capture detailed material data – dimensions, defects, mechanical properties – and integrate it directly into design software to assess suitability for reuse. This enables reclaimed components to be evaluated according to their actual performance rather than their deviation from textbook ideals.

Linked to this is thinking about designing for disassembly and how these materials can be reused again and again in the future. This requires deliberate choices around structural arrangements, connection details, and so on; but also we must ensure that suitable records (whether through digital twins, material passports or simple record drawings) are adequately prepared, stored and made available to future engineers. And whilst this may already be perceived as “best practice”, are we actually doing enough now to facilitate reuse in the future?

Best practice for designing with reused materials will undoubtedly evolve as adoption grows. In the meantime, the profession can rely on first principles, sound engineering judgement, and a readiness to challenge inherited assumptions. By doing so, we can deliver low-waste, low-carbon structures while advancing a more circular model of construction.

Tom Webster is a Board Director at Webb Yates and a Steering Group member of The Engineers Reuse Collective.