« E+C– is a lot of engineering and a lot of sense »
[INTERVIEW WITH : Guillaume Carlier, Group's CSR Manager - Bouygues]
France’s new newbuild environmental regulations (the “Elan” Act) are slated for introduction in 2020. Although these will be a big issue for the whole sector, the BePOSITIVE 2019 exhibition has seen stakeholders showing a united front and the availability of technologies to meet these new standards. Bouygues Building France Europe is a forerunner in tackling carbon issues in building construction. It has input a lot of feedback to the thought process in dealing with these new regulations.
What changes do the new 2020 environmental regulations (“RE2020”) involve ?
First let’s take note that buildings account for 27% of greenhouse gas emissions and 45% of primary energy consumption, making this sector a major action area. RE2020 will link energy performance to carbon and focus people’s thoughts on materials, which represent 80% of a building’s carbon footprint. It addresses not only the choice of materials but also their transport, volume, mix, and eventual disposal (reuse/recycling), radically changing the way buildings are constructed. All-concrete is finished. Exit the all-important logic of prices and lead times; enter a more bespoke approach, where each project must deal with its site, its constraints, and moreover its potential. A new outlook is needed in order to put forward inventive construction solutions tailored to each project, which in turn calls for some high-potency engineering. Project owners aiming for low-carbon performance are turning their sights toward the design-execution markets, which embrace the new, integrated approach to environmental objectives.
Will building to RE2020 standards be more costly ?
When the BBC (low-consumption building) label came out, pre-empting the 2012 thermal regulations, the talk was of a 20% overcost. Today, all new buildings meet those criteria, and yet they work out no more costly. We are still experimenting though, this time with the E+C– (positive energy, lower carbon) label, which anticipates RE2020. The first investment needed is therefore in grey matter. Working and purchasing processes need changing, trades restructuring. And part of that investment is down to project owners, who should bear in mind that the solutions on offer are also cost-savers. In the site phase, for example, sourcing closer to the job saves fuel and transport costs, and using prefabricated CLT sections reduces handling costs and shortens construction times. And then there’s the optimization of occupation costs thanks to lower energy use. RE2020 is stimulating a positive feedback loop, but as with all major changes, the first step is investment, study, and experiment. The BBC Association capitalizes on the feedback from tens of BBCA-accredited construction and renovation projects, enabling fine adjustment of the thresholds set in the future regulations and underpinning their standardization.
What recent building would you single out as typifying the RE2020 approach ?
In early 2016, we delivered 15 homes in the middle of a block in rue des Ardennes, Paris (see photo below). It was a very constricted environment, with all site supplies having to enter through a carriage porch. Then there was an underground car park beneath the site. Instead of demolishing it, we opted for a lightweight timber/concrete construction, using predominantly solid timber CLT. All the earth excavated from the site was reused, giving an overall carbon footprint of –160kg CO2/m² floor area. Energy wise, 35% of the domestic hot water comes from solar heating, while the rest, along with the heating comes from a collective gas-fired compensation boiler. This operation, small as it is, demonstrates that we don’t have to demolish to rebuild from scratch. With a good dose of common sense, constraints become opportunities.
What’s the best way to prepare stakeholders for RE2020 ?
Experiments and sharing of results are essential. For example, in framing the 2012 thermal regulations, not enough attention was paid to user behaviour, yielding poor results compared with those of the models. There’s also a need for venues where professionals can trade ideas, share their feedback, gradually build a new common culture. Trade shows like BEPOSITIVE are very interesting because they make this overview possible by carving out a date for building and manufacturing firms to meet project owners.