Traditionspflege in 286 Teilen: Lehmbau „L’Orangérie“ in Lyon

Rammed earth is pressure-resistant, but it cannot take on any tensile or bending stress without reinforcement. This is precisely what Clément Vergély Architectes and Diener & Diener wanted to avoid at all costs with their Orangérie office building in the Lyon-Confluence district. It also explains the striking façade structure, which features three-storey parabolic arches whose spans measure around 4.75 m each.

Along with three conventionally built and significantly taller residential buildings, the new structure joins a four-part ensemble. The master plan for the quarter, which was prepared by Herzog & de Meuron, foresaw just such a three-storey volume. The architects used this precondition to resurrect an historical regional tradition. Since the Middle Ages, many rammed-earth buildings have been erected in and around Lyon. In the city itself, they have survived only in areas on higher ground, for the floods of 1840 and 1854 destroyed the residential districts near the river. Subsequently, the authorities completely forbade building with rammed earth in Lyon.

The vertical section, and the cross-section of the 11-metre exterior walls of the Orangérie as well, follow the forces that arise within: from bottom to top, the exterior wall thickness decreases from 80 to 65 centimetres, and then again to 50 cm. Altogether, the earth building consists of 286 individual, prefabricated blocks. The base comprises three layers of natural-stone blocks in the same format; as an attic covering, the architects chose quarry slabs whose dovetailing will protect the earth beneath from rainwater. The flat roof above the slabs is lushly planted and accessible to the users of the building. The earth itself is an excavation material from a building site 30 km away, for the dug-up foundation soil in Lyon-Confluence was not suitable for a rammed-earth building. The ceilings and interior supports consist of plywood and laminated timber delivered from the Vosges mountains and Austria.

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Landschaftsarchitektur: Michel Desvigne