Rammed Earth is an old building material that has seen a revival in recent years as people seek low-impact building materials and natural building methods.
Walls are constructed from a mixture of earth that has suitable proportions of sand and clay with an added stabiliser. Traditionally animal blood was used to stabilise the material, but cement is used in modern times.
Formwork is set up creating the desired shape of the section of wall, damp material is poured in to a depth of approximately 250mm (10 inches). A pneumatically powered backfill tamper - something like a pogo stick with a flat plate on the bottom - is then used to compact the material to around 50% of its original height.
A further layer of material is added and the process is repeated until the wall has reached the desired height.
Rammed Earth is excellent thermal mass; it heats up slowly and cools down slowly. Rammed earth is, therefore, not a good insulator. Like brick and concrete (also excellent thermal mass), rammed earth must be insulated in colder climates. Prior to the use of cement as a stabilizer, rammed earth buildings were most successful in dry climates. The addition of cement as a stabilizer has made rammed earth a viable material in wetter climates.
See also
External links
Rammed Earth - The Australian Connection - A good description with photos can be found at this Australia Rammed Earth site.
Stabilized and Insulated Rammed Earth - The first rammed earth builder to build insulated rammed earth buildings that are earthquake engineered.
Historic Rammed Earth - A good site about the history of rammed earth throughout the world, and research into preservation techniques.