50 students from ten European countries participated in the “Zero Carbon Hack” at the global LafargeHolcim Innovation Centre in Lyon, France. Together with a dozen mentors they spent an entire weekend searching for ways to minimize the embodied carbon footprint of a reference building. John Orr, Lecturer in Concrete Structures at the University of Cambridge, United Kingdom, explained why he believes that up to 50% less material could be used in construction thanks to better design.

With global population and urban areas growing at bewildering speed, the world is going to add 230 billion square meters of built living area within the next 40 years – or as John Orr put it, “one Paris a week.” He inspired the students to make an impact by reducing carbon where it really makes a difference: using less material and avoiding errors in construction (that account for about one fifth of the material being wasted). Saving material by clever adjustments to design levers means getting the specifications right and learning from real performance rather than tradition and habits, he said: “If the most suitable construction methods don’t exist, invent them!” John Orr finally inspired the students to think about changes in use and the end of life of buildings already in the design phase, but not to be governed by them: “Think beyond what we have done for the past two thousand years!”

Choosing the right material – but using the minimum possible

As expert at the LafargeHolcim Forum 2019 dedicated to “Re-materializing construction” John Orr (pictured left) contributed to the workshop “Catch 22: Material needs versus material impact” in defining what is the right and the best material – and how material use can be minimized. Obviously, concrete is part of every discussion related to reducing embodied carbon. John Orr showed how the amount of concrete can drastically be reduced by not only using less volume; but using it smarter. He made reference to the work of the Block Research Team at ETH Zurich and of Mark West in Canada who won a LafargeHolcim Award (2005) for “Efficient Fabric-Formed Concrete” which substantially reduced the need of material to reach the same structural result.

Promoting and rewarding sustainability in construction

“Doing more with less” was also the topic of Edward Schwarz, General Manager of the LafargeHolcim Foundation, who used this quote by Lord Norman Foster to introduce the audience to the current LafargeHolcim Awards for Sustainable Construction, including a special category for visions and ideas of the Next Generation. The Forum on “Re-materializing construction” earlier this year built a bridge to the objectives of the “Zero Carbon Hack”. Sandra Boivin, Head of R&D at the LafargeHolcim Innovation Center, and Michael Scharpf, Lead Manager Sustainable Construction of LafargeHolcim, encouraged the participants to think “beyond-the-box” and come up with initiatives to minimize the embodied carbon footprint of buildings.

LafargeHolcim Zero Carbon Hack – Winners Announced

At the end of the final day, a team from Italy, Switzerland and the United Kingdom were announced as winners of the Zero Carbon Hack – with an approach to structural systems and material selection that cut CO2 emissions by 45% for the reference building. A total of EUR 10,000 in prize money was offered including the first prize of EUR 5,000 and a six-month collaboration with LafargeHolcim to further develop the winning project.

The LafargeHolcim Zero Carbon Hack was held in Lyon, France, on November 15 to 17, 2019. LafargeHolcim is the global leader in building materials and solutions. LafargeHolcim created the LafargeHolcim Foundation in 2003 to raise awareness of the important role that architecture, engineering, urban planning and the building industry have in achieving a more sustainable future.