To achieve energy and environmental quality buildings in a viable economic context, it is necessary and essential to tackle the cost of design and construction.
Achieve a cost reduction target of 30% in the building? Other sectors have done it!
In the same way that there was a thermal performance break with the RT 2012, it is now necessary that there be a break on the construction costs, a very significant cost reduction, so a jump in productivity in the act of designing and building.
To analyze how to make this jump in productivity, the first idea was to get closer to other sectors of the economy and industry that have already had such a jump in productivity. What happened elsewhere? There has been very significant progress once a value analysis has been done and the precise constitution of each cost of the chain is redesigned; from conception to realization. It is from the upstream that the whole chain must be redesigned. With a particularly important effort at the design level, anticipating permanently and in an iterative way what would be the future manufacturing costs from the design stage. It is therefore necessary to spend more time in the upstream design phase to better understand the consequences on manufacturing costs, or even maintenance and upkeep.
The building world has seen it, but there is a major handicap because we do not make series but prototypes. The risk immediately brandished was to say that such methods would lead to a standardized and industrialized mass-produced building, the negation of architecture and the return of single thought. However, in the industrial areas cited as the automobile, even those who manufactured prototypes have asked the question: why, even for a prototype, do not think from the design to the realization and its cost? Why not think about exploitation, even the life cycle until deconstruction? Why not think global? In reality, the very notion of prototype does not prevent it, as we will see later.
Virtual mock-up and collaborative work from conception
We can work efficiently upstream with a tool well used in the industry is the virtual model (or digital model). The only arguments against this comparison were to say that, in the automotive industry in particular, the virtual model has been amortized because of series and standardization. Yes, but from the moment when the cost of this virtual model falls, why would not we even pay for the “prototype”?
Industrialization has long been synonymous with standard dimensions, only we realized that with the arrival of the numerical control it was not much more expensive to tailor. The example of the automobile – another form of interior that the building – shows that there are multiple arrangements currently custom, such as colors, customization options from the purchase intention.
The fact of working upstream with a collaborative work on the intelligence and economy of the project, shows that we can, as in the industry, lower the costs in the building.
In the collaborative work, everyone intervenes, designers, manufacturing managers, salespeople who say what customers want, etc … Take the example of the designer in the automobile who would like to incorporate an aesthetic rib on a door. The manufacturing manager will indicate that it causes him 10% of non-quality stamping so 10% extra cost. The commercial will be able to say that this extra cost has no impact on the market, etc., thus, a collaborative and iterative work is established until the designers find other solutions compatible with all the criteria. Aesthetics, manufacturing and market costs.
The demonstration is made that this methodology of collaborative work can be applied to the building if we put around the table all the actors. Take the example of structures cantilevered on the facade of a building. The structural engineer may report to the architect the financial impact. This will be confirmed by the contractor, because of additional immobilized scaffolding or additional completion time. This type of information due to collaborative work may be valuable to the architect who may choose to put richer materials on the facade less “heckled”. In addition, energy savings due to an overall reduction in thermal bridges will result in a much better operating balance over the life of the building.
Site preparation winning intellectual benefit
Another idea that also applies to the building is the period of manufacture, that is to say, the construction site. One of the major features of construction costs is time spent. Fixed assets such as construction cranes, tool hire, time spent by the supervisory and execution staff, etc. In short: the less time the site will take will be expensive.
In addition, a site optimized over time requires you to precisely treat the interfaces between the state bodies. These are the interfaces that can be preponderant in reducing the time of construction and (therefore its cost) and in the costs of non-quality. Admittedly, any reduction in planning must be done within a qualitative framework. It is not a question of decreeing a shorter schedule, to the detriment of quality, but of organizing itself to treat as quickly as possible the interfaces between bodies of state, either upstream at the level of the design, or downstream with semi-industrialized prefabrication methods, that is to say site preparation.
The detailed and concerted design work and the precise site preparation are intellectual services, which even if they lead to an additional cost, say 20% or more, have a significant economic impact on the much more expensive production phase. If 20% more intellectual benefits save 30% of construction cost, the overall economy is important and exceeds 25%! (if we consider a usual ratio of intellectual benefits / construction of 10/90%).
Reinforce the intellectual services upstream of the site, collaborative work and especially the site preparation to reduce the cost of construction and therefore implementation.
Let’s go further, do a collaborative work with industry
The second idea is to work upstream with industry. Indeed, they already have economic methods of manufacture because they act in the first place on the optimization of their components and materials and their assembly. The construction industry can very well, taking into account the concept of prototype specific to the building, achieve pre-industrial equipment and provide from the outset the technical interfaces to other bodies of state and thus significantly reduce the duration of implementation or installation.
Collaborative work must also be established between industrialists themselves. It is no longer a matter of delivering for example a bare radiator, but a radiator with its fasteners already provided for the type of wall. Or, the wall installer can provide the right fasteners in the right place for the defined radiator type.
Beyond the change of behavior of the teams of project management, we will make significant savings if around the virtual model are gathered the industrialists.
Let us not forget that the industrialists are already in the digital age and the virtual model, and that they will be the first to want to integrate into a digital process to manufacture, according to the demand, the standard, the pre- industrialized.