FUTURE FAÇADE PRINCIPLES

Ulrich KNAACK Prof. Dr.-Ing.1

Keywords: guideline façade development, future technologies, smart technologies, sustainability

Abstract The façade technology of the 20th century can be characterized by the dissolution of the massive wall into a separation of structure and façade. With regards to esthetics and construction, the development of façade technology today, after 60 years of curtain wall systems, 30 years of element façade systems, 15 years of double skin façades and 10 years of experience with the integration of environmental services, it seems that the peak of optimization of the existing façade systems has been reached. By continuing the path of adding extra layers for each additional technical function will limit further developments to small technological steps. The research executed in the field of future façade principles as described in this paper offers a collection of potential technologies for different disciplines, which can be transferred to future façade technologies. The collection provides a pool of ideas for architects, designers and engineers with the goal to offer alternative viewpoints or aspects for consideration. They are an offer of technology that we decided to provide to the public - to be used by everyone. The result is a growing potential for façades structures, principles and sometimes even methods of thinking. The challenge of the research is to expand the border of the possible - believing in the idea that as long as the boundaries of the feasible have not been reached, we have not yet reached the full potential. Thus, our research – using heuristic methodologies – will deliver an overview of potential technologies and visionary ideas.

1 Background From a historic point of view, facades have evolved from two structural directions: light constructions based on the requirements of nomadic people, that allow for simple and quick assembly, as well as massive constructions derived from the permanent need for protection at a given location and the locally available materials (1). Following the fulfillment of these fundamental requirements, the facade’s esthetic design developed with the goal to emphasize certain building parts, functions or entire buildings. One example in this context is the step from Romanesque to Gothic. The conception of light in the interior space served as a motor for the development of ever bolder constructions with maximum window dimensions and minimal gravity-loaded vault structures. In contrast, driven by the necessity of functional buildings to be efficiently constructed, industrialization brought about the separation of the master-builder into the disciplines architecture and engineering – with the result of an alienation of these disciplines and the creation of individual esthetic forms of expression (2). One step in the direction of esthetic qualities still favored today is the dissolution of the wall, associated with modernity, into load-bearing components – the building skeleton – as well as enveloping components – the facade. The goal to seemingly dissolve the structure into individual parts created an esthetic form not previously seen (3/4). Today’s developments are – besides various design trends – primarily driven by material-related or technological innovations. This is evident in fully glazed constructions, a trend that started at the end of the last century, whereby the technological finesse is part of the esthetic fascination. Examples are the works by Peter Rice and Ian Ritchie, Mick Eekhout and Rob Nijsse (4/5). The conception of glazed double facades must be considered as part of this development. In addition to a continuing dissolution of the envelope, this concept also tried to fulfill the demand to optimize the building climatically, since the many winter gardens proved as climatically and energetically problematic and a longer usable period was required. A generation of double facades evolved that, with its four main 1 Chair Design of Construction, Faculty of Architecture, TU Delft, The Netherlands, Ulrich.knaack@tudelft.nl

variants second-skin façade, corridor façade, box window facade and shaft-box façade, was no longer merely a building envelope, but rather an integral part of the building’s climate design by integrating climatic concepts (3/4/6/7). Figure 1 – Facade Principles : second-skin façade, box window façade, corridor façade and shaft-box façade (1) Based on this fact, the next step – the integration of building services into the facade – seems logical, maybe even mandatory. Particularly if one considers the in-depth planning requirements and high level of prefabrication needed for facades and building services elements, as well as the dramatic increase in complexity. The projects Posttower Bonn / Helmuth Jahn with Transsolar and Capricon in Düsseldorf / Gaterman + Schossig are examples of the developmental steps described – both integrating building services modules into the facade. At the same time, several suppliers have worked on incorporating these technical possibilities into their products – such as t-motion by Wicona, smart box by CEPEZET as well as E² by schüco – however, these products have not yet been implemented on a large scale (1/6/7/8) Figure 2 – Facade principles with building services integration: ventilation, humidification, light (1).

Figure 3 – Façade Posttower Bonn In parallel with the above described development, a trend toward further research and development of new materials can be observed. The research mainly focuses on materials for the building envelope, with the goal to create formative innovation by material innovation. This, of course, again creates a multiplicity that becomes part of the overall concept. On the downside trends are being set by using terms such as ‘smart’ or ‘nano’; in many cases abusing the potential by merely using these terms for branding purposes (9/10/11). Figure 4 – Façade Capricon Bonn

2 Today’s drive In the course of investigating the parameters influencing the planning and building processes, the following topics were identified as technical corner points of an area of tension that encompasses the new developments and conception of facades in addition to esthetic trends: energy, efficiency and individuality. Energy as the motor for all actions, paired with the actuality of the energy market and the climate change. Efficiency in the sense of performance expected from the facade as a technically sophisticated building component. Individuality as part of the architecture that reflects the particular urban, spatial and esthetic form of the building (12/13). It quickly becomes apparent that the above mentioned parameters require a high degree of technical competence with regard to development, planning and realization of facades; especially the integration of functions poses a difficult problem, since these functions might contradict or even exclude each other. Thus, expenditures for further development become increasingly complex, which in turn poses the question of the relationship between expenditure and benefit. We can summarize citing Michiel Cohen (CEPEZED), remarking in closing his lecture at the first “The Future Envelope” conference in 2007 in Delft: “The future has to be simpler” (12).

3 Future facade principles Against the background of the above described situation, the Facade Research Group was formed at the Delft University of Technology in 2005. This group is currently engaged in various topics related to facade technology: problem solving oriented research with the goal to provide solutions to short-term problems – e. g. issues with facade refurbishment or the manufacturing process of free-form facades – as well as to develop working methods and tools to standardize planning procedures and technology transfer. For these research areas the group employs traditional scientific methods by establishing statistical data, evaluating constructional and technical solutions, developing new technologies for specific issues as well as developing planning tools and methods (12). Figure 5 – Facade Research Group of the Faculty of Architecture / Delft University of Technology

4 The method - Imagine Series Another focal point is the development of visions for the future development of facades. The goal is to generate potential development methods with the associated discussion and evaluation of technical possibilities identifying design, manufacturing and structure related options for the designer. The aim is not to solve concrete technical problems, but rather to change the traditional working method to a new approach that offers possibilities and options as a starting point for new designs. Here for, the group uses conventional tools for new developments to ensure that the development process is controllable as well as traceable, even if the results can not be predicted. The group follows the train of thought of De Jong – to travel from “technological research” to “design research” to “study by design” without necessarily following straight-lined developmental steps (14). Figure 6 – Future façade principles – Category Concept (17) Figure 7 – Future façade principles – Category Concept (17) Key factor of this approach is the belief that even coincidental predictions can enable focused and resilient developments. The group uses the heuristic method with the following working levels: engagement, immersion, incubation, explication and creative synthesis (15). Workshop participants come from different target groups – students, architects, engineers, climate designers as well as façade planners. Depending on the situation they provide either quick innovative ideas or conduct multi-day seminars to generate topic oriented or completely free developments. The working method of choice is brainstorming which, with the parameters “collect as many ideas as possible, all ideas are welcome, no discussion, do not criticize, documentation of all ideas, set time limit” has proven to be successful and versatile (16). However, this free brainstorming phase is followed by an evaluation of the individual solutions presented as well as technical and esthetic post processing to organize the ideas systematically and prepare them for documentation in digital and printed form. Figure 8 – Future façade principles – Category System (17) Figure 9 – Future façade principles – Category Deflateables (18)

The ideas are organized in different categories such as concepts (results, which are expected to be realizable in the future), systems (ideas related to principle construction and not specific technical solutions), deflateables (results based on vacuum stabilized construction), materials (constructions based on the use or development of material related solutions) and adaptables (principles using ideas from different disciplines or technologies). The interest of the Façade Research Group is to enhance the possibilities for everyone rather than keeping them hidden away, because if something is not used or applied it is not relevant. The results of the Future Façade Principles are a growing amount of ideas for facades or skin structures, principles or even methods of thinking (17/18). Figure 10 – Future façade principles – Category Materials (17) Figure 11 – Future façade principles – Category Adaptables (17) 5 Conclusion Building on existing knowledge and employing classic scientific research methods – problem outline, compilation of material and knowledge, evaluation and interpretation, structuring and lastly the development of subsequent steps – the group employs the idea of heuristic development in order to faster identify future developments and their potential and risks. Thus, in addition to gaining knowledge about individual technological options, we learn to quickly assess and evaluate them. The analysis does not only consider purely technical parameters (construction and energy) as deciding factors for whether or not a certain technology is worth pursuing but also social and economic criteria. An example: The reason why building services integrated facades, one of the above mentioned topics, have been hard to realize is not only due to their technical complexity – but rather the difficulties of the economic process: areas of responsibility and issues with the concrete realization of the product are difficult to define and solve (12). But this example also shows how different the reflections of the possibilities can be, for example for the executing companies: system suppliers are more interested in all-in-one solutions that do not facilitate an exchange of components whereas manufacturers of customized solutions want to streamline the engineering process. Interestingly enough both processes have one thing in common: motivation for innovation originates in the design – either from a special formative idea and/or a specific technical solution. Thus, the Posttower Bonn as well as the Capricon project in Düsseldorf (1/8) as interconnected solutions were only made possible because the integration of building services components into the façade followed a clear formative as well as a technical approach. This leads us back to the starting point of the developments of technical ideas for the Future Facade Principles: developing possible scenarios to motivate the designers to strive for new formative and technical solutions. It is the reversal of the traditional planning principle, which was to solve the technical issues created by the design through targeted development of technical visions and depiction of the resulting design possibilities. It is obvious that with this method not only the best but also ideas of lesser quality are being pursued and realized, because factors other than the technical and formative parameters come into play. However, it is exciting to see which trends develop through the core of the formative, technical and economic possibilities, and sometimes being able to influence these trends through new developments.

References (1) Knaack, Klein, Bilow, Auer: Principles of Construction – Facades; Birkhäuser – Basel, Boston, Berlin 2007 (2) Kohlmaier, G; von Santory, B: Das Glashaus – ein Bautypus des 19. Jahrhunderts; München 1981 (3) Thomas Herzog, et al, Facade Construction Manual; Basel/Boston/Berlin 2005 (4) Knaack, 1998: Konstruktiver Glasbau: Müller Verlag Köln (5) Wurm, Glass Structures, Basel/Boston/Berlin 2007 (6) Oesterle, Lieb, Lutz, Heusler; Doppelschalige Fassaden; 1999 München (7) Pottgiesser; Fassadenschichtungen – Glas; Berlin 2004 (8) Compagno; Intelligente Glassfassaden / Intelligent Glass Facades; Basel/Boston/Berlin 1995/2002 (9) Brownell; Transmaterial 2; New York 2008 (10) van Uffelen; pure Plastic – new materials for today´s Architecture; Berlin 2008 (11) Ritter; smart materials – in Architektur, Innenarchitektur und Design; Basel/Boston/Berlin 2007 (12) Knaack, Klein: The Future Envelope – a multidisciplinary approach, Delft 2007 (13) Knaack, Hasselbach: New Strategies for Systems, Delft 2006 (14) De Jong, van der Voordt, 2002: Ways to research and study urban, architectural and technology design; DUP Delft (15) Kim Etherington: “Heuristic research as a vehicle for personal and professional development” Magazine Counselling and psychotherapy research, 2004 – vol 4, no2 (16) Kleining, Gerhard, Witt, Harald: The Qualitative Heuristic Approach, Forum Qualitative Social Research, No1, Art 13 (17) Knaack, Bilow, Klein, 2007: Imagine 01 – Future Facade Principles, 010 Rotterdam (18) Knaack, Bilow, Klein, 2007: Imagine 02 – Deflateables, 010 Rotterdam