Hanif Kara on building materials, the transition from old to new, and a healthy dose of realism

Hanif Kara is calling for calm. It's true; in the hierarchy of building materials, long-standing stalwarts are facing a major image crisis. It’s not difficult to see why. As the construction and real estate sectors battle to reduce their colossal carbon footprints, non-renewable materials harbouring high levels of embodied carbon such as concrete and steel are problematic in their current form.

In the midst of the frantic race to build better, the world-renowned structural engineer flags that we are at the start of a 20-year transition period. One that will not only see natural materials being deployed more frequently, but which will allow for necessary research and testing to be done to “clean up” others he believes are being unfairly vilified.

Hanif Kara - 'The days of building with anything in abundance are over'

'The days of building with anything in abundance are over,' says the co-founder of London-based structural engineering practice AKT II. 'But that doesn’t mean we should demonise steel and concrete rather than trying to make them better. Nor should we overemphasise the benefits of materials like straw and mud bricks because you can’t build with those at volume.'

The engineer’s role, he says, is to help the wider real estate industry navigate the transition from old materials to new with a healthy dose of realism.

A smooth transition

While Kara, who became the first engineer to be awarded the Soane Medal for architecture in October this year, is committed to showcasing the successful use of natural materials, there remain limitations to widespread deployment.

The 2024 AlMusalla pavilion in Saudi Arabia made from palm wood composite - AKT II’s suggestion - is a prime example. A powerful demonstration of what can be achieved using traditional, regional materials. But until the technology to sustainably manufacture and build with them is readily available, they are an unrealistic replacement for non-renewables on a large scale.

Trialling and testing cleaner versions of concrete and steel is one way of plugging the gap. Kara is characteristically bold on this and AKT II led one of the first uses of Earth Friendly Concrete (EFC) piles on British Land’s 53-acre Canada Water project in November 2020, saving 240 tons of carbon emissions.

The practice has also been working with Imperial College and an affiliate company called Seratech to patent and deploy an aggregate in concrete that will make the product cleaner by eliminating the need for lime and cement – “the guilty party” – and give it carbon capturing qualities.

And while Kara might disagree with the demonisation of materials like concrete, he fully supports eliminating their use where possible. 'The way we analyse how buildings sit on the ground has got a lot more sophisticated,' he says. 'This means we can ask ‘do we really have to pile it’? The industry does not always need to take the overabundant approach we have all become so used to.'

Hope at the cliff’s edge

One of the most obvious opportunities for balancing materials old and new is retrofitting. 'You often find there is a lot you can keep,' says Kara. 'The Arding & Hobbs building in Clapham is a current example of this. We worked out how to take the building from what it was to what it needs to be and asked ourselves ‘by keeping that [material] can we still put the building to use?’ Then we have had to choose our new materials very carefully - and that’s where the research into cleaning up concrete and steel is so important - so as not to cancel out everything we are saving. Can we use less steel? Can we find better steel? Or second-hand steel? These are all conversations going on across the industry around retrofitting.

'There are so many things being tested and researched, and a lot of people are working very hard to address the impact of building materials on the planet,' he adds. 'Despite the fact we can see the cliff’s edge now, there is a trajectory of improvement. And that gives me a lot of hope. We are heading in the right direction.'

akt-uk.com