The main objective of the COST Action C13 was to increase the knowledge of properties and possibilities of glazing in order to increase the performance of building envelopes, to reduce the energy consumption and to improve the quality of life with respect to interior space, impact on the environment and human welfare.

This collection of papers presented at meetings and workshops of the COST C13 working groups 1 (Architectural Aspects and Design Integration), 2 (Quality of Interior Space) and 3 (Structural Aspects of Glass) are the result of 5 years of exchange of ideas, experiences and know-how between members, delegates and experts. It represents the body of knowledge from a restricted but representative group of professionals in Europe on the subject of glass building envelopes.

The Steel Structures Laboratory at Ecole Polytechnique Fédérale de Lausanne (CH) and the research group 'Façades' of the faculty of Architecture at Delft University of Technology (NL) have taken the initiative to publish these COST C13 papers in order to disseminate the knowledge to the world of glass façade professionals and to contribute to the development of a new generation of high-performance glass building envelopes.

One of the main conclusions of COST Action C13 is that the three worlds of Architecture, Building Physics and Structural Engineering are today by far not sufficiently integrated. Additional efforts are clearly required to align these three worlds into a holistic entity that is able to design building envelopes that are optimised with regard to all three points of view.

The reader is encouraged to read the separate articles, to reflect on the content and to contribute to the future development of innovative building envelopes by writing novel contributions in the field. Preferably these contributions are interdisciplinary and try to integrate all facets of the subject, from fundamental research topics via technology development issues through to the application in architecture. All of these domains are supposed to stimulate each other rather than living apart together.

Delft, August 2006

Prof. Dr. Mick Eekhout, Prof. Dr. Ulrich Knaack, Ronald Visser; Delft University of Technology, the Netherlands

Lausanne, August 2006

Michel Crisinel, Matthias Haldimann; Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland