L’Express: In recent years, the computer and digital revolutions have upset the business world, leading to hypermobility of employees and outsourcing of work. Trends accelerated by the Covid crisis, which has profoundly transformed the use of offices. Is this the end of tertiary buildings?
Sylvain Grisot: No, but the changes you have just mentioned question above all the nature of the spaces and their location. It has become difficult to spend two hours on public transport to arrive in an open space where you disturb your neighbors at each videoconference meeting. There is a form of absurdity today which makes the office gradually impose itself as the best place not to work. Let’s start with the location of buildings: whether they are in the city center, in business centers like La Défense near Paris, or on the outskirts of cities, they are often the last places where we want to to live. Driving to work is also a barrier, in contradiction with the values of employees.
On the business side, the sizing of the premises raises questions. Do we have too many square meters when 20 to 40% of employees are teleworking? The answer is obviously yes. Then, the new types of management with their less strict hierarchies are also pushing to rethink spaces, beyond simple meeting rooms. You have to make people want to come to work at the office! Finally, recent events are precipitating these transitions: the explosion in the cost of energy, the increase in charges as well as new regulations in tertiary construction, etc. All of this is accelerating the obsolescence of a large number of seats which have in common that they are badly located, badly insulated and badly designed.
What happens to these buildings that have not been able to adapt to changes in the world of work?
That’s what I call zombie buildings, not yet wasteland, but already condemned. Companies today prefer to rent hundreds of square meters of collaborative workspaces closer to the places where employees live rather than these office buildings of the 1980s and 1990s, further accelerating their aging. So either we start from scratch by destroying, or we change the use.
You are talking here about urban recycling. Is this the solution for tomorrow? Transforming offices into habitats?
Some buildings have potential when they are well located, but remain exceptions! Construction standards in the tertiary sector (hospitals, offices, businesses, car parks, restaurants) are over-specialized for greater efficiency, which limits their adaptability to new uses. We are moving away from the principle of resilience which is rather associated with forms of sub-optimization of buildings. Sometimes, the best response to urban obsolescence is to permanently destroy these buildings and undertake the renaturalization of the site. But this idea of degrowth still seems badly accepted in France, where we still speak of “crisis” and revitalization, hoping that it will pass. However, we can no longer index the future to growth alone.
In this case, can we or should we still build something new?
AIf tomorrow I had a heart condition, I would be happy to be taken care of in a recent and well-equipped hospital. Building new is possible! You simply have to think about the relevance of the project upstream and remove the hyperspecialization reflex. Hence the importance of public policies… If you decide to build, then you have to think in the long term and not forget that a building can have several lives and change use twenty years later. For example, the number of levels and interior partitions should be limited. With each new project, we must be guided by other imperatives: what is the carbon footprint, where are the materials? A building is designed in several layers and they must all be able to evolve independently.
More specifically, what do you recommend?
Focusing for example on the interior fittings: the furniture, the floors, the false ceilings… All of this changes quickly and without consequence. Then there is the partitioning by limiting the number of load-bearing walls, which are very restrictive since they prevent the offices from being enlarged or the space from being transformed into housing. Next, we have work to do to improve the facades most exposed to bad weather and which will inevitably suffer from aging and technical obsolescence. In thirty years, it will be necessary to be able to change the windows, the joinery or the photovoltaic sensors without impacting the rest of the building.
Finally, the most expensive element in terms of materials, investments, but also ecological impact and which must be preserved for as long as possible, is the structure, especially when it is made of reinforced concrete. Most CO2 emissions come from the manufacture of cement and steel. Cement is also a doubly emitter, and even if we try to create low-carbon concretes, with reductions of a few tens of percent of emissions, these are above all stopgap measures and not real breakthroughs. On the other hand, if the structure is voluntarily oversized and does not impose the uses on the site, it then makes it possible to anticipate the needs for change and to extend the life of our buildings in the long term.
Beyond buildings, the other evil is urban sprawl. To get out of construction at all costs, you introduced the concept of circular urban planning. What does it mean?
Initially, my thinking focused on land use, then I broadened it around the idea of making the city. That is to say a city aware of the waste it produces, the materials it consumes and the scheduled end of life of its buildings. The concept of circular urban planning comes down to anticipating, before the first pickaxe, four “loops” of solutions. The first is to…not necessarily build if you don’t need to. I knowingly take the example of an office building with meeting rooms on the ground floor, used occasionally and on weekdays. We can give the keys to associations that would come there in the evening or on weekends. In this way, the square meters are made profitable, avoiding the town hall having to build a house for associations and offering the company additional rental income… This is the intensification of the city.
Second loop: transformation. Do not demolish when you can and lose the carbon investment by producing waste… Thirdly, when we cannot find the answer to our needs in existing buildings, we must build in already urbanized areas. This is densification. Finally, the last lever: urban recycling, which is developing more and more, in particular thanks to the government’s “wasteland fund”. Each of these solutions remains difficult to implement with massive adaptation challenges. But if we succeed, 80% of the city of 2050 is already there.
For further : Let’s fix the city! Proposals for our cities and territories, by Christine Leconte and Sylvain Grisot. Apogee Editions, 2022.