nexttech.be
en
The knowledge platform for technology, innovation and digital transformation
2025 got off to a special start for the 150 administrative staff and directors of Eiffage Construction BeLux, Valens and Eiffage Real Estate Belgium. On 6 January, they were introduced to their brand-new workplace. Located on Gustave Demeylaan in Oudergem, several subsidiaries of the group joined forces to transform a typical 1990s building into The Source, a smart open-plan office environment that encourages synergy and collaboration. What's more, with its ultra-modern headquarters, Eiffage is also setting a new standard in terms of CO2 reduction, energy efficiency and circularity, further reinforcing its burning ambition to become the pioneer in low-carbon construction.
‘If you want something done right, do it yourself,’ is a common saying in the construction industry. Judging by The Source, this unwritten rule certainly seems to hold true. Eiffage Group put all its know-how into creating a future-oriented home base for its three Brussels entities, which were previously spread across two separate locations in the heart of the capital. “The aim of The Source is to create better synergy between our various companies and departments. And the building also clearly illustrates our expertise,” says Patrick Colas, project manager at Eiffage Real Estate. “I myself acted as the client's representative during the implementation process. So it was up to me to ensure that the work proceeded according to the planned schedule and in the manner envisaged by Valens, Eiffage Real Estate and Eiffage Construction BeLux. Building for yourself is not an easy task in theory, but in practice we hardly noticed it. Our companies were already used to working together, so once the project team was up and running, everything went very smoothly.”
However, Eiffage Construction BeLux did not choose the easiest route. Instead of constructing a completely new building, it opted for a major renovation. An environmentally conscious choice, explains Patrick Colas. “The Eiffage Group has the ambition to significantly reduce its CO2 impact, so that was a crucial guiding principle in this project. By starting with an existing building, we were able to significantly reduce the CO2 footprint of our new headquarters. Given our group's desire to remain firmly anchored in the Brussels region, we opted for an office space in Auderghem, which dated from the late 1990s and was previously owned by a banking and insurance institution.
Not only was it located in an easily accessible location, in a quiet green neighbourhood undergoing rapid development, but it was also in relatively good condition and had an interesting structure. Thanks to the corner morphology and limited construction depth of thirteen metres, we were able to guarantee sufficient natural light throughout the open-plan office floors, without creating a dark central core. And by retaining the existing concrete skeleton, we were able to save 852 tonnes of CO2 straight away. The substructure and sanitary cores also remained intact. However, the technical systems, interior design and façade were completely renovated.”
The Brussels-based firm R²D² Architecture was commissioned to give architectural form to Eiffage's plans and ambitions. “We had already worked with them in the past – for example, on the Vandergroten project for citydev.brussels – and we were very pleased with the results,” explains Patrick Colas. “We asked them to come up with a design that would create a wow effect from the very first glance. Our new building had to be a real showpiece and therefore needed to have a strong visual identity. The original façade, which had been out of fashion for some time, was replaced by a transparent three-part façade. The idea was to use a louvre system that would not only guarantee an aesthetic appearance, but also prevent overheating. The thermo-lacquered aluminium louvres are positioned and oriented – depending on the façade on which they are installed – in such a way that they block excess sunlight before it reaches the triple-glazed curtain wall behind. In this way, they create the necessary shade during the hot summer months and reduce the cooling load of the building. On top of this, a diagonal steel structure has been installed that extends to the roof. This serves to stiffen the whole structure and also fulfils a decorative function. The roof and façade thus flow seamlessly into each other.”
The Source is also a real eye-catcher from a technical and energy perspective. However, Patrick Colas emphasises that an important conceptual decision was just as much at the heart of the intended CO2 savings. “By rationalising the use of space and thinking carefully in advance about how we wanted to work in the future, we were able to reduce the surface area we needed by 50%, from 6,622 m² in the past to 3,113 m² today. Combined with energy-efficient technologies such as an innovative CO2 heat pump powered by PV panels and a whole range of smart building applications that maximise comfort and allow us to closely monitor energy consumption, this makes a big difference. The lighting (which is automatically adjusted in terms of colour temperature and intensity to the biological rhythm of those present), heating, ventilation and security are connected in real time via an advanced building operating system. Numerous sensors and detectors have been installed in all rooms to measure occupancy, humidity, CO2 levels, etc., allowing us to continuously monitor how many people are in a particular room at any given time. This enables us to optimise both the operation of our building and its energy management. Our employees can use their smartphones to book meeting rooms, control the temperature, adjust the lighting, and so on. In short, we have left nothing to chance. As a test, we even installed a Renewind urban wind turbine on the roof. We have therefore gone to great lengths to fulfil our promise of low-carbon construction.”
The latter also applies to the use of materials. In line with the circularity concept, Eiffage opted to use as many recycled materials as possible. “During the demolition phase, we dismantled a lot of interior elements that were later reused, such as raised floors, doors, toilet bowls, and so on. This was not easy because we had to store them on site, but it was worth the effort. Some of the floor coverings are also recycled, although it was obviously impossible to find approximately 2,000 m² of the same type of carpet. That is why we have installed two different variants per floor, with a ‘warm’ colour on one side and a ‘cooler’ colour on the other. The same applies to the ceramic tiling in the sanitary areas, which varies in the men's and women's toilets. In addition, a third of the office furniture from our old premises has been given a new lease of life here. This has resulted in an ideal mix of existing and new materials. The fact that the façade construction consists of 20% recycled steel also fits in perfectly with our sustainability goals.”
From an architectural point of view, the asymmetrical roof structure posed the biggest challenge, says Patrick Colas. “Not only does the roof slope, it also changes angle. With the help of digital technologies, our sister company Sabem ❯ managed to come up with a truly groundbreaking solution. Although surprises can always crop up in renovation projects like this, the execution went almost flawlessly and the connections were almost immediately correct. Other companies in our group also contributed to the construction of The Source, such as Reynders (fixed furniture), Solufak (audiovisual equipment) and Duchêne (joinery). For all parties involved, this project was a unique opportunity to gain experience with this type of renovation, which will become increasingly common in the future given the rise of circular construction and the growing shortage of available building plots in our region. We were able to learn valuable lessons in both construction and property development. As we were acting as the client ourselves, we also had the freedom and flexibility to test certain things. A good example of this is the staircase we built in low-carbon concrete from our sister company Vuylsteke-Eiffage, which we might not have dared to do in another project. Such test cases have provided us with many new insights that will certainly enable us to make a difference in future projects.”
After eighteen months of hard work, Eiffage Construction BeLux's Brussels entities were finally able to move into their new headquarters at the beginning of January. “It was an exciting moment, but the reactions were extremely positive. Everyone is very proud of the end result. We've only been here a few months, but it feels like we've been at home here for years,” beams Patrick Colas. “Moving from a traditional office environment with lots of individual office spaces to an open space where paperless working and a clean desk policy are the norm is no easy feat, but the transition went very smoothly. We did everything we could to ensure that our employees could resume their professional activities without disruption after the Christmas break. It was a race against time to complete the move and the provisional handover on time, but when everything turned out to be working perfectly afterwards, the satisfaction was all the greater. The realisation of this new headquarters gave us the opportunity to streamline our office operations, and we are already reaping the benefits. The open layout encourages social interaction, and the relaxation area on the top floor – which includes a ping-pong table, table football and a spacious roof terrace – also contributes to the pleasant working atmosphere. The beautiful artwork on the ceiling perfectly encapsulates The Source's DNA. It depicts a swarm of bees, symbolising the team dynamics that Eiffage Group strives for. There's no better place to work together to build a more sustainable future!”
