It is a privilege to work within the innovative field of the construction industry. Especially since we probably are in the middle of what at the end will appear to have been a revolution. The contemporaries of James Watt were not aware that they were part of what we now call the industrial revolution. Only on looking back we were able to determine that the changes were quite drastic and that it merited the label of revolution. I am convinced that something like that is happening in our era. Developments in the field of a.o. industrialization, energy and climate, environment, automation and digitalisation, lack of labour, new materials, are quite significant and are forcing us to re-evaluate the field of construction as a whole. For that reason it is to be expected that during the coming decades building technology and its process will change drastically. There is thus a strong need for innovative visions about future construction.

I was invited to act as a peer reviewer for this book about the future envelope and in line with that to write this preface. Through this I am pleased to have the opportunity to contribute to the discussion on building innovation.

The starting point for the Façade Research Group are also the driving forces for development: Energy, Ecology and Efficiency. From a societal point of view I agree on the 3E mindset. One of the major tasks however is not to jump to solutions immediately but to define the targets within these areas more specifically and in a measurable way. That is not an easy job. There are a lot of stakeholders in the building industry and they probably all have their own agenda and as a result their own drives for development. It is important to define these drives carefully (with repeatable research results) as the total programme will be based on such a point of departure. Measurability is crucial in order to be able to monitor future results.

It is proven that a systematic approach increases the rate of success substantially. This implies the need for firm strategic analyses before addressing the research content. In his contribution, Wim Poelman reaffirms the necessity of a systematic approach. Here the routine of the industrial designer is contrasted with the architectural approach that is mostly based on rational and irrational considerations on a project level. The façade industry may be one of the most advanced disciplines in the building industry. Still the percentage of buildings with progressive, innovative facades is in the minority. According to Rogers' diffusion theory, modern facades are still only for the innovators and early adaptors. It is often stated that the building industry is conservative. There are many explanations for this phenomenon. The complexity of the supply chain with fragmented interests is one of them. Broadly accepted change therefore will not come rapidly. We can expect our revolution to range over the next few decades. Still, from year to year we will increasingly come across visible milestones.

It is understandable that in a technical university the focus is on technology, but one should keep in mind that technology cannot be separated from a broader vision. We need a cohesive picture and some research effort, perhaps in cooperation with some non technical universities, is of relevance. The majority of innovation achieved will consist of new products. However, design tools and new approaches to process will explicitly have to be part of the progress to be made. Tools can for example help to benefit of new technology visibly. This is about creating values. For example soundly based productivity figures for building users could stimulate the application of advanced façade technology drastically. It would be a fantastic driver to have reliable tools and models to convince commissioners on this point. Perhaps this may even turn out to be an even greater act of innovation in terms of change than façade development itself. It is however interesting to bring the facade in relation to the building concept and the utility question as a whole. In such a context volume reduction (lean walls and partitions) could be an interesting example of creating value as the user has substantially more space at his disposal within the same gross measures of the building.

An important process issue and part of my own research programme (Slimbouwen) is the organisation of the industrial process which is much more than just about producing parts with industrial technology. The research on an industrial building process focuses on creating a situation in which contractors on building sites are able to work without interweaving with other disciplines. In relation to facades the question for example is how to deal with services. Integrated with connecting leads for connection with the infrastructure (the façade as a machine) or disintegrated with accessible hollow spaces in the elements. The industrial approach will most certainly lead to other forms of project organisation including the design and preparation phase as well as, for example, new technologies for joints facilitating the industrial process.

A resetting of the building process as a whole is unavoidable. We just cannot go on with solving problems on an ad hoc basis. As a result of the fragmented supply chain we have been innovating incrementally on step by step basis on a component level. It is as Michiel Cohen in his contribution says that we are solving problems and at the same time introducing new ones. The result of this is that the regular building process has meanwhile developed into quite a chaotic, inadequate and highly inefficient process in which disciplines are very much interwoven with each other.

A major part of the content of the book is directed towards solutions and original ideas. It could be considered as technology driven input. That is a very good thing to do in order to inspire and challenge the market and also to be able to have discussions on the basis of concrete material. A.o the frozen textile and sandwich structures in the aviation industry are interesting topics and relevant to the building industry. Weight and volume reduction are very relevant drivers for innovation in relation to cost control and sustainability. Ultra light (and rigid) structures are however very bad preconditions for achieving a sufficient sound insulation. A deeper understanding of acoustical behaviour might create openings for this technology.

Technology can be very inspiring. It is however good that the book also focuses on non technological topics. I would like to take the opportunity to call attention to items such as issues of strategy and the analysis of customer desires and demands. The customer should become more visible in the building market. Anyway, new business approaches will no doubt form another basis for future developments. It would be interesting to make an extensive inventory of possible future business models in order to feed the strategies for developing new facades. The drivers for innovation are also not all of a rational nature. In the contribution of Luke Lowings it becomes clear that also emotional, symbolic and perceptual values become important, and are perhaps underestimated drivers for development.

I hope that you the reader will feel challenged to join the creativity or to evaluate your own ideas about the future in order to keep the discussion alive. Every contribution is of relevance as long as it sincerely supports future development. Universities have, of course, a special mission to take the lead in developing long term visions and future scenarios in order to create a fecund soil for breakthroughs for the benefit of the entire building industry. This book is an inspiring example of just that.

Prof. Dr. Jos Lichtenberg, Eindhoven University of Technology, Faculty of Architecture Building and Planning, Chair Product Development