The concept of sustainability has risen in the last three decades, as a vehicle to guide our efforts to overcome major environmental and societal challenges such as global warming and environmental degradation. The built environment is responsible for about 40% of the global CO2 emissions, a fact that has led to countless debates, approaches, and new technologies for the design of our buildings, and especially, the building envelope. The goal of this paper is to explore the current role and the impact that sustainability has in the design of the building façade, based on the insights from practicing architects with relevant experience in the field. While we know of countless theoretical approaches and design theories to deal with sustainability, the point of view from practitioners has hardly been in the spotlight. So, the input for the assessment was obtained through a series of interviews with designers, representing 34 different architectural firms in the Netherlands, between January and April of 2020. The 34 interviews followed a semi-structured questionnaire comprising open-ended questions, structured around different themes concerning their façade design process. The present document showcases and discusses the results from the following questions: what is the role of sustainability in your façade design process? How does it influence the result? The exploration of the gathered information shows that within the broader scope of sustainability, circularity is the most mentioned set of aspects that currently have a clear impact on façade design, closely followed by energy related aspects, and further below issues related to the user, nature inclusion, and value. Furthermore, it is possible to identify different and sometimes clashing approaches derived from different notions of sustainability: some interviewees believe in permanence and timeless buildings, which leads to massive structures and detailing focused on ageing and durability; while for others it mainly revolves around using less raw materials and reuse/recycling potential of building components; which leads to light structures, with focus on connections aiming for total disassembly and material recovery. These, among others, should be regarded as possibilities to choose from a set of potential approaches, whose suitability should be carefully assessed to match each project brief, under the larger aim to design and build sustainable façades, buildings and cities.@en

The aesthetic of our built environment is perceived as an important aspect to consider for the design of human-centred cities, but a problem quickly arises in the presence of clashing conceptions of what we understand to be aesthetically pleasing. This paper adds to this discussion, by exploring architects' aesthetic preferences in façade design, aiming to include design practitioners in a debate that so far has remained largely academic. Thus, the goal of the study was to identify relevant aspects, based on a series of semi-structured interviews with practitioners representing 34 architectural firms from The Netherlands, carried out from January to April 2020. It was possible to identify two major types of aspects, and subsequent subgroups. Intrinsic aspects (compositional, plastic, detail design, and character) comprise aspects that are characteristic of a façade as an object, while extrinsic aspects (human, intellectual, and contextual connection) consist of relational features, determining the perceived beauty of a façade in terms of its connections with an outside agent. The main identified aspects in each one of the groups, the potential relations among them, and their relative relevance within the surveyed sample were part of the assessment, comparing the outcomes against previous results from the literature.@en