Material choices

LafargeHolcim France launches carbon configurator as the country advances toward carbon neutrality


The sweltering-hot Paris summer this year confirmed yet again to Rodrigue Leclech that the world needs to move fast if it wants to beat climate change. Rodrigue specializes in energy efficiency in buildings. “We didn’t expect temperatures to reach 40 degrees Celsius in the summer before the year 2030 but in fact it’s already happening now.”

Rodrigue helped LafargeHolcim France develop a digital carbon configurator called Lafarge 360 Design, enabling design offices to calculate the projected CO2 impact of the foundation and superstructure of new residential buildings. Out of a total of fourteen structural elements of new builds, these are the two that have the highest carbon impact. The calculations take into account local specifications, norms and building regulations. The tool gives a first estimate but does not yet replace a more in-depth study of the design that also includes the thermal envelope or energy use. It is however becoming ever more accurate as new projects are continuously being entered into the tool, with now currently around eighty projects delivering data.

“360 Design comes at a crucial time as the focus is increasingly shifting to the construction industry,” he says. France has committed itself to achieving carbon neutrality by 2050 and is facing the massive challenge of renovating the currently existing building stock and decarbonizing the construction industry as a whole. The construction industry accounts for 45 of the country’s energy needs and over a fourth of its greenhouse gas emissions. The country introduced thermal energy regulations on buildings (Régulations Thermique, RT) in 2012. The fifth since 1979, and is bracing for new, tougher regulations in 2020 that will require new homes to have an improved carbon footprint across their full lifecycle. To help ease the transition, France introduced a voluntary certification scheme in 2016 called “E + C-” to reflect the environmental performance of new builds. It rates both energy consumption (E) and the carbon impact across its lifecycle which encompasses the construction phase, an operational phase of around 50 years, plus the end of life phase.

The scheme will become law in 2020 and is expected to have an important impact on the use of concrete. “Concrete has firmly established itself in the last 60 years as a traditional building material in France but our understanding of its carbon impact is still not well understood,“ explains Rodrigue. “This is where the tool will make a difference as it gives an indication of the carbon footprint of the concrete selected, and can influence the choice of materials used for the building.”

Rodrigue expects to see a greater mix of building materials in the construction industry in the future, combining concrete with wood and others. But it’s clear that concrete is here to stay: “Concrete has amazing properties that make it an ideal building material so for sure people will continue to build with it. But it’s vital that we improve its carbon footprint, and that’s why we will continue to work closely with the building materials sector to help achieve this.”

Photo below: Rodrigue Leclech – consultant in energy efficiency, with Paris based consultancy Pouget