Digital fabrication has great potential for improving the sustainability in construction. However, until now this potential had hardly been investigated. Research at the NCCR Digital Fabrication now aims to identify the significant parameters of this emerging technology and provide a knowledge base for project optimization.

The design of digitally fabricated architecture already leverages the knowledge of how it will be built early in the development phase. By knowing the materials and assembly methods earlier in the process, the impacts on costs, energy and material consumption can be calculated and optimized. Research in this field however up to now has mostly focused on formal, technical, structural or performative aspects of a design. The overall assessment of the digital fabrication parameters, in terms of sustainability, is still lacking.

The main goal of a recently launched research project at the Chair of Sustainable Construction at the ETH Zurich is to develop guidelines to help designers and industry make sustainable choices in the implementation of digital fabrication. “Research into sustainability needs to be performed now while digital fabrication is in an experimental state, so adjustments can still easily be implemented” explains Isolda Agustí Juan, the lead researcher of the project.

Four categories of impact

Approaches to digital fabrication can be categorized as reductive fabrication (such as milling or cutting), or additive fabrication, which is widely associated with 3D printing. Previous studies on the environmental profile of 3D printing have already identified reduced waste production as a key opportunity in additive fabrication, but there is also strong potential for the reduction of CO2 emissions, energy and resource consumption when compared to reductive fabrication. Yet, at full-scale, architectural construction exceed the capabilities and the logic of 3D printing. Digital fabrication of architecture is driven by a complex balancing of material, performance and regulatory issues. It therefor requires unique methods and technologies to achieve the expectations of industry, and also new frameworks for assessment.

The methodology developed at the Chair of Sustainable Construction at the ETH Zurich is based on an understanding of the interdisciplinary research being undertaken at the NCCR Digital Fabrication as well as the international standards for the life cycle assessment (LCA present in ISO 14040:2006). On the base of a preliminary assessment of digitally fabricated prototypes four main categories of intervention have been identified. In each of these categories the combination of computational modelling, material sciences and robotic fabrication has large potential for project optimization by enabling:

  • Additional functions: structures can be enriched with additional functions (e.g. thermal, acoustic performance) without raising the overall costs, increasing new opportunities for sustainable design.
  • Efficiencies in construction processes: construction processes can be planned ahead and adapted to the specific requirements (e.g. reduction of waste, improving quality of work) to increase efficiency and sustainability in construction.
  • Reduction of materials: the form of a structure can accurately be adapted to the flow of forces, addressing sustainable and resource-efficient construction.
  • Use of alternative materials: on site fabrication with locally available and unconventional materials, which can lead to the generation of novel design and more sustainable buildings.

Material production as biggest lever

For each of these four categories the research will evaluate the impacts associated to the making, implementing, and operation of buildings. This includes the energy (embodied and operational) and resource allocation involved in both the processing (i.e. build-ing materials, computers, robots, etc.) and the construction.

Climate change impacts of the processes involved in the digital fabrication of 1m2 of self-shading brick façade (Source: Agustí-Juan, I. and Habert, G. Chair of Sustainable Construction, ETH Zurich)

The so far most relevant research findings of the life cycle assessment can be summarized as:

  • The production of building materials is the highest impact on the environmental profile
  • The resource and energy impact of digital fabrication technologies is very low or almost insignificant compared to construction
  • Research into construction processes with alternative and low embodied-energy materials should be broadly investigated.

This means: Any improvement in the efficiency of producing construction materials or reducing waste material will be far more significant than the impact of using digital fabrication technologies. Therefore, if through the use of digital fabrication methods it is possible to optimize materials and resources in construction, then digital design and fabrication methods can contribute significantly to improving the overall sustainability of construction.

This conclusion however should not to be misinterpreted as a categorical statement that robotic fabrication is more environmentally friendly. Rather, the statement clarifies that by knowing the consequences of material and process costs, and by optimizing potential benefits, it is possible to achieve significant gains in sustainability using digitally driven methods.