From Grey to Green

A look at some of the figures contained within the first report from the Concrete Industry Sustainable Construction Forum should dispel any doubts as to its significance. Every year the UK concrete industry produces 38 million tonnes of precast products, some 23.5 million m3 of ready-mix, and consumes a staggering 100 million tonnes of raw materials.

To anyone but bankers perhaps these are very large numbers and, inevitably, the industry attracts the attention of environmentalists who question the effect it may be having on the planet. Certainly, concrete’s environmental impact cannot be denied. Quarrying and heavy transport are the obvious visible evidence, while the hefty carbon footprint of cement production is probably the biggest single issue.

So the first thing to note about the report is that it does not shy away from such figures, having the courage to publish the very numbers that the industry’s critics might use against it. But then it is the stated aim of the forum to assess the concrete sector on a number of sustainability criteria. It further promises to repeat the assessment in future reports, and to set in motion measures to help the industry become more sustainable.

And the report is far from bad news. Some of the figures are genuinely encouraging and help put the industry into context. Those 100 million tonnes, for example, sound less frightening when put with Friends of the Earth’s calculation that at current usage the UK has aggregate resources available for many thousands of years. Consider too, that a quarter of aggregate consumed in the UK is actually recyclate, and that the concrete industry uses more waste product than it creates. Some may be surprised to learn that the cement sector uses 315,000 tonnes of processed waste materials as fuel amounting to some 20% of its total fuel usage, or that the carbon footprint of cement production has been reduced by 27% since 1990.

Writing in the forward to the report, environmentalist and founder of Forum for the Future Jonathon Porritt says: “We have been genuinely impressed by the progress made and the quality of leadership shown.”

Credit: Tim Soar

For this warehouse restoration for Southwark council’s new green HQ, architect AHMM used concrete to great effect – harnessing its thermal mass for a low-energy cooling, heating and ventilation system.

But what does the construction industry at large make of all this? Is the report seen as just a sop to the greens? Or is it viewed as a herald of real change that will impact on designers, contractors and engineers?

Brian Spires, director of sustainability at HLM Architects, is positive: “What impresses me most is that all the major players in the industry have got together in an industry-led initiative to benchmark performance and encourage it to improve,” he says. “Compared with many other materials suppliers concrete seems to have got off the mark sharper and quicker – though I guess that may be because of the environmental focus on them.”

Whatever the motivation, Spires says the report has come at a good time: “Concrete is important,” he says. “The industry has to make its use as sustainable as possible and be seen to be doing so. In producing a readable and believable report, detailing where the industry is and stating clearly where it needs to go, the forum has done a very good job.”

Sarah Kaethner, associate director in advanced technology and research at Arup, also welcomes the report. She was involved in some of the stakeholder working groups that helped to shape it. “The key thing about the report for me is that it is seeking to get hard information about the impact of construction materials out into the public domain,” she says. “We don’t want to be told this material is good, or that material is bad. What we want are the metrics by which we can do good design and reduce environmental impact as much as we can. Everything else is greenwash.”

What kind of use then, can designers like Kaethner make of the information contained in the report? “Concrete is a material where you have some ‹ flexibility to change the specification,” she explains. “Different cementitious materials, different aggregates, different strengths – all these can be within the specifier’s control. If you have the data, you can understand the impact of your decisions and design more intelligently.”

And different figures, says Kaethner, can be used at different stages of the design process. Take, for example, the figures on the carbon footprint of concrete transport: the report reveals that the average journey from ready-mix plants is 8km – a figure which rises to 150km for precast products, though the average vehicle tonnage is double. “These can be used as generic guidelines and then compared with the specifics of an individual job,” Kaethner says. “It’s also useful to have agreed industry figures – on cement replacement materials, for example – instead of the differing figures from various sources as before.”

Credit: Tim Soar

The Westminster Academy in north London has won many admirers – not least on the 2008 Stirling Prize jury – for its solid but graceful design, making a feature of exposed concrete walls.

Kaethner hopes to see more life-cycle calculations added to the mix in future reports. And she echoes Spires’ point about the co-operation needed to create the forum in the first place.

“It really matters that these large carbon producers are getting together, identifying what should be measured and how, and sharing information between competitors,” she says. “It sends a strong message up the supply chain and strengthens the case for sustainability across the industry. I’m glad it’s no longer on the ‘too hard’ pile.”

Her last point is an interesting one. Whether the concrete industry makes a real difference to the planet will inevitably depend in part on co-operation throughout the supply chain, and a coming together of various members of the construction team.

The point is strongly illustrated by Peter Goring, technical director of specialist concrete contractor, John Doyle, who tells an interesting story about the specification of concrete on a recent job. On the Coleman Street project in east London for Stanhope, engineer Arup recommended an environmentally-friendly concrete, one that used waste granite from china clay extraction. The waste material was only incorporated because of specifier influence, Doyle’s co-operation in making an effort to source it efficiently, and the client’s willingness to pay a premium for the product. Any one of the parties could have proved the weak link in the chain, but on this occasion a more efficient use of materials resulted and the project won an environmental award. One would hope the forum’s efforts would foster wider co-operation and understanding of this kind, but Goring cautions against too much optimism: “The report is fine,” he says. “The concrete industry needs to improve its environmental credentials. But I’m not sure it’s going to change how we work.”

Contractors, says Goring, are economic pragmatists who only bring change forward if it is commercially viable to do so. “If we set ourselves standards that our clients don’t want, or don’t want to pay for, we would preclude ourselves from working and that wouldn’t be right. Suppliers drive what’s available and clients drive what is wanted – we are caught in the middle and have limited influence.”

But Goring may be selling himself short here. As a specialist contractor Doyle cannot ensure, but can certainly encourage, the consideration of more sustainable products – and knowledge disseminated by the industry bodies must only improve the reception such options may receive.

Architect PRP ZEDFactor used concrete for sustainable as well as aesthetic ends at the St Matthews keyworker housing scheme in Lambeth. It achieved not only Eco Homes excellent, but far higher standards of thermal efficiency than on most Excellent schemes.

He makes another point, about costs, which also might be amenable to the forum’s efforts: “Some suppliers charge more for eco-products because they have invested to get it to market,” he says. “So we embrace better materials as long as clients are prepared to pay the difference – that’s if there is a difference. I think sometimes there shouldn’t be a difference, but there is because people are unfamiliar with the material.”

His concern here is shared by Kate Mansfield, associate with architect PLP: “It’s good the industry is looking at innovative new products with a low environmental impact,” she says. “But architects and contractors are used to using certain products. How do you get them to change? It’s often purely a commercial decision. Are the new products cost effective?”

And she agrees with Goring that suppliers may sometimes up the price of an “eco-product” for reasons which are more to do with marketing than production costs: “They may charge for the eco label and even if they don’t, specifiers might think they will!”

There is obviously scope for improvement here: if the industry market development body, The Concrete Centre, can support the consideration and production of better materials and inform the construction industry about them, then designers and contractors will surely find it easier to advise clients on the options and to source the ones that tread most lightly on the earth.

This is really something of a culture change and no one expects the publication of a report to achieve it overnight. As Randall Ffrench, a designer with Sir Robert McAlpine, puts it: “The forum has identified some good targets, some good principals and I feel there is real commitment to achieving the improvements it discusses. It will be for future reports to tell us how successful the industry has really been.”