The central feature of the Turntoo method is a passport that bears indications of every single material utilized to assemble the ‘circular cathedral’ of Driebergen-Rijsenburg (and many other projects around the world): a serial document to catalogue the materials used, so that in the future not even the smallest scrap will become refuse, but will instead be ready for reuse. In the vision of Rau and Oberhuber, “waste is made up of materials with no identity.” To give them one means assignment of legal (and economic) recognition that can transform them into resources. This is why the couple has created Madaster, the cadaster of materials, as they call their invention. Many companies around the world have already decided to wager on it. “Hundreds of clients,” they say, “have registered a total of over 2000 buildings for 7.5 million square meters of construction. With the Madaster database, constructions have been catalogued in the Netherlands, Switzerland, Germany, Norway, the United Kingdom, Finland, Spain, Belgium and Taiwan.” At the moment there are no projects under way in Italy, where no one has stepped forward to date to formulate what Rau, Oberhuber and the director of Madaster, Pablo van den Bosch, call a ‘coalition of the willing,’ an alliance of local players supported by the Dutch team, who believe in the idea and set out to fully develop it with the required perseverance.

Madaster is an online platform that automatically generates the materials passport. “The intuition came when we were thinking of an enormous library of materials. To work with this method in building means being able to inventory materials in advance, making it possible for designers and builders to adapt their techniques in such a way as to construct an entirely demountable building. This prevents waste and constructions can be recouped and reinserted in a new production process, without losing their value. If I have a definite project and I insert it in the database, the software encodes it and indicates the list of necessary materials.” For this, the Triodos Bank is a demountable and re-mountable building for which we know the exact number of bolts – 165,312 – which are all ready to be removed and reutilized for years in other projects.

The first building made with a catalogue of its materials via passport, in 2011, was a small town hall in the Netherlands. At the time, the database was merely an Excel file, far from the sophistication and levels of complexity achieved later by Madaster. Yet that sketchy intuition was sufficient to attract, among other things, the attention of Google. The Mountain View giant wanted to find out more about Dutch know-how in this area. Since then Madaster has become the official tool of the Building Passport report organized by the Global Alliance for Building and Construction, coordinated by the United Nations Environment Programme. Rau and Oberhuber have narrated their philosophy and know-how in a book, Material Matters (published in Italy by Edizioni Ambiente), which is now spreading the word.