With concealed lintels, the suspended rammed earth is tied to the loadbearing beam of reinforced concrete or trass-lime with the bolts. If the construction is to have cladding on the interior, the support beam can be set on the inner edge of the rammed earth wall, as is the case with the large studio window in the Rauch House. As a result, the outward-facing layer of earth is thicker.
The lintel for the openings situated above the wide gates of the Kräuter-
zentrum in Laufen was fabricated with two thermally insulated steel girders. Since the façade here is composed of prefabricated elements, the beam was integrated during the ramming process rather than being installed on the building site. This type of construction can also be readily used for in situ wall construction. In either case, the steel lintel must be inserted in a slightly raised position. The load of the earth positioned on top of it will then press it down into its final position. In order to protect the edge of the rammed earth wall, the lower flange of the girder is fitted with an angled profile, which provides a precise edge for the lintel and precludes excessive erosion of the earth on this edge.
Integrating lintels directly into rammed-earth elements opens the way
Diagram left: Detail section of the
for earth building to explore new paths of formal development. The windows
lintel in the Chapel of Reconciliation.
and doors of traditional rammed earth structures are tall and narrow. For a
The rammed earth wall is visible on both sides and the underside of this beam is covered with earth. Lintel construction detail at 1:10 scale.
long time, wider openings were technically impossible to create – horizontal fenestration and broad lintels have only become feasible in combination with other materials.
Diagram right: The gates of the Kräuterzentrum in Laufen with a steel girder rammed into the wall element. Section at 1:10 scale. Trass-lime check Rammed earth façade 45 cm
Rammed earth wall 60 cm
L-profile 200 x 20 with thermal separation Thermal separation
Reinforced trass-lime mortar
Edge trim
30 x 32 cm
Rectangular hollow structural section frame
96