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Ricola Kräuterzentrum in Laufen
2015 ¥ 3 Concept ∂
“Suddenly, with earth, everything fell into place.” An interview mit Pierre de Meuron
Pierre de Meuron was interviewed by Emilia Margaretha.
DETAIL: The “Kräuterzentrum”, or herbal centre, in Laufen is the latest in a series of projects that Herzog & de Meuron have planned for Ricola. What is the underlying concept? Pierre de Meuron: On the one hand, the long-standing collaboration between Ricola and Herzog & de Meuron plays a major role in this project – the dialogue with the client, his requirements, the technical and functional expectations set in such a scheme, as well as the location where the building was to be erected. On the other hand, there’s the theme of herbs and the construction material, rammed earth – another two important cornerstones of the project. DETAIL: What requirements were formulated by the client for the new structure? de Meuron: First of all, various processes were laid down: harvesting, drying, mixing, cutting and storing the herbs, which suggested a linear form. As an architect, though, the programme is not the only element of the brief. The location has to be taken into account as well. We had the same concepts as the client from the very beginning. It was also clear that it had to be an imposing structure in order to respond to the neighbouring high-tech building. The new herbal centre was to demonstrate the importance of herbs for Ricola and for the process of manufacturing its confectionery. DETAIL: In other words, it was to be a striking building, but not necessarily spectacular? de Meuron: Precisely – not too conspicuous, or expressive. On the one hand, the site lies in the middle of open fields; on the other hand, the task had a lot in common with that of an agricultural building. The first idea, therefore, was a timber barn, and this led to a clear form with a rectangular plan – initially with a double- or single-pitched roof. But a timber outer skin would have had a smaller mass, which would have made additional ventilation and air-conditioning plant necessary internally. What’s more, timber as a material would have resulted in legislative problems in the context of food-processing hygiene. Then we had the idea of construct-
ing the buildng with earth, and suddenly everything fell into place. The typical moisture regulation of earth works positively in relation to the processing and storage of herbs; and in terms of energy, it has a sustainable effect on the entire indoor climate. The density of the walls lessens temperature extremes, so that the energy consumed by mechanical services is reduced. What’s more, earth has been excavated in Laufental for centuries, so that the building was created from the location, so to speak, from the ground. It was a kind of “aha” effect – the only proper solution. DETAIL: The development of the project took a long time, while the process of implementation was extremely brief. Did you have to acquaint yourselves first with the material and the form of construction? de Meuron: It was a completely new form of production and construction. At first, we didn’t know how and whether it would work. A lot of things had to be clarified – not least the costs. We could have opted for a very simple building envelope of corrugated sheet metal. From the outset, though, the clients were prepared to invest a greater sum and, as with their wooden high-bay warehouse in the early 1980s, they were aware that additional costs for the design of the building skin represented a greater value for the company. DETAIL: How did that work: on the one hand, the wish to experiment, and on the other hand, having to keep a close eye on costs? de Meuron: Martin Rauch was a great help in that respect. Without him, it wouldn’t have been possible. From the outset, we needed a specialist, and fortunately Martin Rauch is only a short distance away from us – in Vorarlberg. DETAIL: What influence did Martin Rauch have on the development of the project? de Meuron: We developed the building jointly. Martin Rauch is one of the leading earth construction specialists in the world. To clarify crucial questions, such as what the com-
position of the earth should be or how large the elements could be, we worked on a fullsize mock up. The danger with earth construction is that water can erode the material. A key question, therefore, was how to prevent the building being washed away by rain. For a structure with the dimensions of the herbal centre that was a fundamental issue, of course. DETAIL: How did you resolve this? de Meuron: Strips of trass-lime mortar were tamped into the wall elements to retard erosion. In this way, the water can be made to flow along the wall more slowly or to drip off. The 40 cm roof projection acts as an additional form of protection. DETAIL: How was your collaboration with the others who were involved in the project, especially in view of the initial situation: the fact that a structure of this kind had never been built here before? de Meuron: The task was a demanding one and challenging. It could only work, of course, if mutual respect existed between all the parties involved and the main goals were made clear. Only when all these aspects have been resolved can an object like the herbal centre in Laufen be created. Time and money both played a major role, too. Initially, the earth elements were to be fabricated in Vorarlberg, but then we rented an empty hall not far away and implemented the newly developed technology for the very first time – close to the site. DETAIL: Couldn’t the load-bearing construction have been made of earth, too? de Meuron: The dimensions of this building are enormous. Traditional earth structures in Africa or the American South-West are much smaller, and the roof is usually executed in a vaulted form. Like stone buildings, earth structures can bear only compression loads, not tensile ones. In the case of the herbal centre, we can define the facade as an outer skin, an enclosing wall in earth. And within it stands the production and storage building.