Hors-Site and BIM, a winning duo to improve productivity in the construction sector

Overall, the design of a construction project is studied from a blank page, without integrating a standardization process which makes it possible to rationalize the methods. Added to the “tailor-made” of a project, compliance with new environmental regulations, the significant increase in the cost of raw materials, not to mention a tougher financial context where interest rates are on the rise.

Without profoundly rethinking our design and construction methods, it will be increasingly difficult for our sector to reverse the productivity curve and improve performance. Fortunately, pragmatic solutions are already within reach of players: off-site industrialized construction and BIM.

Two working methods, 1 common rule: anticipation

Whether off-site construction or BIM, these two methods play a key role right from the design phase.

From the DfMA - Design for Manufacturing & Assembly, off-site construction allows building components to be manufactured and pre-assembled, off-site in workshops or factories, for installation and assembly at the final location. Particular attention is paid to the elements of the final assembly before any manufacturing launch in the factory. This makes it possible to reduce hazards during the construction phase, and even during operation.

This state of mind is all the more shared with the methodology of BIM (Building Information Modeling) which makes it possible to model the information of a building or a set of buildings. In the same way, this approach intervenes very early in the projects. Even before the building comes out of the ground, the building and its technical components called “objects” are materialized virtually in a 3D digital model. By adopting a BIM approach, the identification of blocking points is anticipated and corrected more easily from the design stage.

Standardization and modeling, 2 optimization factors

Once again, off-site construction and BIM have the common ambition of optimization. Industrialized construction is by definition a standardization of construction elements which should enable builders and project owners to better rationalize costs and deadlines, while reducing environmental impacts and accidents on site. In BIM, the data of the objects making up the virtual building are just as standardized. Each object is assigned characteristics. Thanks to 3D building modeling, it is possible, for example, to easily carry out simulations in order to test the environmental quality of materials, or thermal insulation during design. Applied to industrialized off-site construction, BIM is an additional tool for building more efficiently.

Industrialization… but different designs thanks to BIM and its parametric modules

If we have to integrate more industrialized processes in construction projects, the objective is not to standardize massively and to uniformize either. The architect must obviously maintain his role as creator of urban space, by proposing a building adapted to each environment and each lifestyle of the occupants. What he must know is to recognize the forms whose construction rules are repeated in his project in order to rationalize them, and thus consider his project off-site. Parametric modules can be a response to the desire for uniqueness in projects.

In off-site construction, manufacturers rely on families of modules. Take, for example, a timber frame load-bearing wall with an integrated window. This module has fixed parameters like height, thickness, interior coating, etc. These parameters allow, based on a single module, to create hundreds of different designs. We can also imagine even more complex modules such as a bathroom, a stairwell, or even a well-defined model of a hotel room. These parametric modules can be families of objects in a BIM model. Thus, the architect can combine these modules endlessly to achieve the desired design within a standardized framework. These families of objects can also contain all the data necessary for manufacturing. Manufacturing plans or machine orders for the factory can then come directly from the model.

The BIM and off-site construction duo should therefore be studied more closely in France to solve a persistent problem in the construction industry: improving the performance of construction sites.

Tribune by Constance DE BATZ, President of MBAcity (LinkedIn) and Elia ABOU-CHAAYA, Off-site & Modular Activity Director and Ile-de-France-Nord Regional Director at BTP Consultants, Chairman of the CSTB QB-Modular Committee (LinkedIn)