Rammed earth is one of the oldest forms of building with rammed earth structures found to be old as 8000 years. Rammed earth construction was used on ancient sites in Mesopotamia and the Great Wall of China. Rammed earth structures have now been built on every continent except Antarctica.
Rammed earth works on the principle of compacting a damp mixture of clay, gravel and sand into formwork. The mixture is sometimes stabilised with various materials for added strength ranging from animal’s blood, lime and more recently cement in a 10-15% mix but this is not necessary and companies like Ram-Cast never use stabilisation in any of their buildings.
The formwork needs to be 30-35cm wide but also extremely strong as the earth left in the formwork will be the final wall and any deformities due to formwork warping will be evident in the final wall.
Rammed earth works upon the principle that you compact the earth in the formwork to half the original amount and then keep adding earth and compacting it until the earth is at the top. You can then remove the formwork in order to texturise the earth to your preference. The earth will continue to set, gaining strength as it does so. It can take up to two years for the walls to be completely set. The exterior walls need to be sealed in order to stop water seeping into the walls.
Rammed earth with jazz
Rammed Earth with David Sukuki
Next rammed earth house
Rammed earth with Rowland Keable