Building techniques

Rammed earth is a thousand of years old building technique and is a widely used. Crumbly, soil-damp and relatively lean silt matter is poured in layers into a mould and compressed mechanically. A certain advantage of the rammed earth technique is, that the mixture of silt, sand and gravel often appears in nature and is perfect in its characteristics for this building technique. With this in mind, 50% to 100% of the excavation material without top soil can be used for building. Rammed earth is a very solid, its density can be compared to concrete and its specific weight is, according to the mixture and its location from 1,8 to 2,2 t per cubic meter. Its best use is for load bearing earthen structures. Also for heat storing in glass houses and in the combination with heating systems can the technique be applied technically and creatively. The handling of the earth masses requires a contemporary, mechanical conditioning and a rational building site management. Silt and clay has the positive effect that it can be conserved damp in its conditioned state over weeks or years. The quality of the material can even be improved through the storage (Mauken).

With the Pisee-technique the silt and earthen mixture is compressed periodically in horizontal layers of roughly 12cm thickness in the mould. The crumbly, soil-damp mixture is poured in layers and is compressed with air compression beaters and vibration rolls. After every third layer, a mortar layer is mounted on the mould edge and also compressed into the mixture. Alternatively stone or brick sheets can be used. A working section and mould section is 15 m to 20 m long at the maximum and not higher than 2,8 m. The vertical alignment splices to the next wall section come up in an angle of 40°. At a storey-high mould the wall thickness is usually at 60cm, as the mould has to be accessible for the compression procedure. On smaller mould sections the thickness of the load bearing walls can be reduced, according to the structural purpose, to 20 or 40 cm.