Zijlstra, architect and founder of Materia, an independent advisory office for the selection and development of architectural products and materials, discussed the use of materials by Mike Guyer and Annette Gigon from Switzerland. These architects are experimenting with a form of concrete to which steel particles have been added. Exposure to air causes the steel to oxidise and the concrete turns a rusty-brown colour. Another concrete experiment is being carried out by Herzog & de Meuron, who are experimenting with concrete-retarding etching techniques on concrete facades by suspending the effectiveness of solidification elements locally.

Beukers, of the Faculty of Aerospace Engineering at Delft University of Technology, wrote the book Lightness together with Ed van Hinte. His credo is 'more performance with less material'. Since oil is becoming scarcer and labour more expensive, materials have to perform better, according to Beukers. For him, the task for the future is lighter buildings. Innovation in materials will mainly stem from the aviation and aerospace industries, where a lot of experience is being gained in the area of light materials (it costs around 20.000 guilders to send just 1 kilogram into space). The future is one of inflatable buildings: pneumatic structures with a minimum of material, maximum volume, and optimal performance. They are a good alternative to much too heavy modern buildings. Beukers also predicts a good future for multi-layered textiles strengthened by the addition of carbon-fibre with resins. At the TU Delft, a number of products have been developed with this material, among them a light spare wheel (10 kg instead of 40 kg) and a beer keg.

Mick Eekhout (Professor of Product Development, TU Delft) was somewhat critical of the new materials. How do you apply them in the context of current regulations and terms of guarantee? According to Beukers, there needs to be a change in thinking and mentality in terms of regulations. A good example in his view is the Ministry of Transport, Public Works and Water Management. The maintenance of infrastructure is very expensive, and carbon-fibres are therefore being used in bridges and viaducts now to reduce the level of maintenance required. Apart from maintenance reduction, buildings should be developed in such a way that they can be reused. Beukers mentions the possibility of strengthening bearing structures by wrapping them with foil and netting.

Some architects, as we know, are always searching for materials that are hip and advantageous. Both Zijlstra and Beukers see textiles as a major trend. Significant advantages are: industrial prefabrication, straightforward transport of foldable structures, simple assembly, resistance to vandalism, strength, and seamless structure. An interesting example is the application of textiles in the construction of luxury yachts. The hulls of these yachts are made seamless by pouring textile and resin into huge moulds. Els Zijlstra finished with a tip for the calculating architect: go to the supplier of semi-finished products, where material costs just a fraction of what the supplier of finished products asks.