27 Jul 2026
There’s lots to learn from the reinvention of Denys Lasdun’s 1980s IBM Building as a bang-up-to-date office (page 18). Projects like this are inspiring not only because they give architectural icons a new lease of life – and sometimes right the wrongs of a previous age – but also because they can tell us a lot about how to equip new buildings with longevity.
One of those lessons is that a concrete structure can last significantly longer than the original design life – structural analysis on the IBM Building (now called 76 Southbank) found that the concrete was much stronger than assumed, and that the substructure could bear an increased load of up to 30%.
Making buildings last as long as possible is at the core of circular thinking. By reusing an existing structure, we not only preserve the carbon in its construction, but reduce the need for new materials. Increasingly the expectation is that buildings should be able to be adapted, and that a retrofit will at least be considered before demolition.
So I always wonder why we still measure whole-life carbon over a default period of 60 years. Many structures have a design life that is far longer, illustrated by the other projects in this issue: 100 years for Melbourne’s State Library station, and 120 years for Kengo Kuma’s portico at Angers Cathedral (itself dating from the 13th century).
Liverpool School of Architecture is expected to last well over a century too. In the UK, the key guidance document is the RICS Whole Life Carbon Assessment Professional Standard. This has been really important for providing guidance, alignment and clarity around conventions, and for driving greater measurement.
But it’s worth noting that 60 years isn’t a universal limit. Both the RICS methodology and the European standard upon which it is based, EN 15978, allow assessments to be based on other periods of, say, 80 or 100 years, where they are a better fit to the estimated service life of the building. Much longer service lives are expected on infrastructure projects, and this is already reflected in the standard assessments period for these assets.
In housing, on the other hand, the default period does not reflect the fact that many UK homes are still in occupation after a century or two. The Future Homes Hub has been creating conventions for the whole life carbon assessment of new housing which uses the default 60-year period but acknowledges that many houses will have a longer life cycle. The RICS document adds that for domestic projects a 120-year assessment should be undertaken for the envelope, but I have never seen this discussed or applied.
Many layers of a building won’t last anywhere near that long, but a well-designed structure can and should. The trouble with measuring things over a short period of time is that it can lead to short-term thinking. If you don’t plan for something to be long term, you’re not facilitating it.
Standards are continually evolving as our understanding of carbon accounting grows, and measurements are our best guess at reality, rather than a direct reflection of it. There are many variables in a whole-life calculation, and it does become more difficult to predict the outcomes over a longer period.
But that doesn’t mean we shouldn’t try – embodied carbon was once on the too-difficult pile. The industry has come a long way since then, but there is still much further to go to decarbonise new construction and existing buildings. Making sure we’re using the right metrics is an essential step on the journey.
By Toogood, Senior Director, Concrete, MPA