Interview with Marina Da Silva Carvalhais, R&D projects and Wood Construction Innovations (WeWood / Bouygues Construction R&D).
Why should we rethink the design and construction of schools, colleges and high schools?
Today, in France, a significant majority of these buildings are built on site, and still primarily as concrete structures. But the environmental situation we are experiencing is compelling us to change, and in particular to increase our use of wood construction and off-site construction. Bouygues Bâtiment France Europe also aims to achieve a 30% share for its wood projects by 2030, and McKinsey expects a 20% share of global construction to be moved to off-site construction by this same deadline.
On the other hand, the “traditional” method of constructing this infrastructure often generates nuisances for the inhabitants and the communities: noise, dust, odours, increased road traffic, etc. Contracting authorities and companies naturally seek to limit these nuisances. Off-site construction makes this possible, while shortening the duration of on-site work, and improving conditions for craftsmen: sheltered from bad weather in a workshop, working with wood rather than concrete, etc.
But when building school equipment partly off-site using wooden structures, it is essential to plan this construction method from the start of the design. This is possible when working on design-build projects, and assuming all project stakeholders share the same ambition,and project management in particular.
Local authorities also expect ever less carbon-intensive and more scalable school development projects that are capable of adapting to demographic changes in their regions.
What does the Ship My School project consist of?
In a project partnership between Bouygues Bâtiment Île-de-France Ouvrages Publics, WeWood and the manufacturer Technologies & Habitats (T&H), we designed a solution of wooden classroom modules that are prefabricated and pre-equipped in the factory. Because contrary to what has been seen in some of our projects, not only the structure and envelope of the classroom is prefabricated: we have conceived it as a space – a product that is all but completed in the factory – incorporating as many ancillary services as possible, to be “plugged into” the general infrastructure.
And why focus on classrooms? Because with standard needs and recurring programmes from one project to another, classrooms – which represent about 50% of the surface of a secondary school building – are ideally suited to the design of a modular construction product, as well as industrial production.
We have therefore closely examined the programmes of many high schools and colleges to identify the specifications of a typical classroom. Considering criteria for technical facilities, interior finishes, acoustics, fire safety and ceiling height, and adopting the most demanding constraints where applicable.
This led us to work in five areas:
- Floorspace management and architectural principles of façades;
- Sizing of structural elements;
- Integration of technical terminals and networks, feasibility and interfaces with the technical trades for the rest of the building conducted on site;
- Incorporation of architectural building trades, feasibility and limits of services;
- Implementation methods (supply, quality control, temporary watertightness, lifting, etc.)
The challenge is to offer a basic design that meets the identified scheduled requirements, governed by a design guide previously sent to project coordinators, specifying the technical requirements imposed by the construction method, but nevertheless capable of adapting to the specific characteristics of each project in terms of façade openings, orientation, ALJ and thermal requirements, surface areas, etc. No one wants buildings that are all identical, or schools that look like temporary facilities!
What are the next milestones for this project?
The next big step is the creation of a prototype, and we’re already working on that. It will make it possible to verify certain performance in two different ways: most obviously in terms of acoustics and airtightness, but also – and more importantly – to demonstrate in practical terms what this solution can do, and to prove that industrial production can go hand in hand with high quality.
The other big step is the drafting of the design guide for use by the project designers, as mentioned above; this will specify the basic principles, including both constraints and opportunities.
We are also working on the accuracy of the overall cost of the solution, as its off-site costing method differs greatly from what would be used for a conventional construction site. Next, our goal is to further develop the basic solution, particularly in terms of roof modules to allow accessible roof configurations, photovoltaic panel supports and more generous earth thickness. We are also working on the feasibility of specific facilities such as science rooms.
What do you think the construction of public facilities will look like in 2030?
France will have to meet its national targets for reducing greenhouse gas emissions, and labels will become ever-more demanding: construction methods will therefore need to evolve so that our buildings set a better and better example from an environmental point of view.
I see it as involving more wood, of course, with the use of concrete limited to strictly necessary places such as foundations, infrastructure and areas where the architectural concept and the technical and scheduling requirements justify its use. I also imagine we will see less reticence over the use of other bio and geosourced materials such as hemp, or raw earth.
And, of course, as envisioned by the McKinsey report in 2030, I see it as being partially carried out off-site. Because I don’t believe in buildings that are entirely prefabricated in the factory, at least not for the moment: off-site construction will be used where it is most relevant, and in particular in classrooms!
Projects will be faster, and will generate less nuisance for residents, for the environment, and for site workers. Public facilities, such as a school, college or high school, are designed to play a specific role in local urban life; and I believe it is essential for them to be in harmony with that life, starting from the construction phase.