Innovation with Depth: The multilayered rammed earth wall of the Walkeweg Auditorium, Basel

Multilayered and Precise: The Construction of the Rammed Earth Exterior Wall

The exterior wall of the auditorium is designed as a multilayered construction, consisting of load-bearing timber–earth elements on the inside, an insulation layer, and a prefabricated rammed earth façade on the outside. Both the inner and outer layers are prefabricated and then assembled on site. 
 

Layers at a glance:

1. Interior: Timber frame elements with rammed earth infill
   The inner layer serves as the structural basis. Rammed earth is placed between the timber ribs in the workshop, contributing not only to indoor climate regulation but also creating a natural contrast with the timber. The curved surfaces of the earth infill and the timber supports also enhance the acoustics of the auditorium and shape the interior atmosphere. 
2. Insulation layer
   The two prefabricated wall systems are separated by an insulation layer, which ensures the overall thermal performance of the assembly. 
3. Exterior: Exposed rammed earth elements with erosion barriers
   The outer prefabricated rammed earth façade is presented in its natural state. On the weather-facing side, controlled erosion is anticipated: in the first years, fine particles are washed out from the surface, gradually revealing the coarser aggregates – a natural, desirable ageing process without structural impairment. To slow down erosion over the full height, horizontal fired brick bands are integrated.

Early Sampling: Mock-up by Lehm Ton Erde

To review the construction aesthetically, Lehm Ton Erde produced a mock-up that was assessed by the entire team. It demonstrated not only the final appearance but also the feasibility of the prefabricated timber–earth elements on the inside.
 

The rammed earth wall of the Walkeweg Auditorium in Basel illustrates how a traditional building material can be integrated into a highly modern, prefabricated building system, convincing not only in its aesthetic qualities but also in ecological and building-physics terms. A model for the future of building with earth and timber.