Rammed Earth:

Rammed Earth is a type of construction method, which involves the compression of a damp mixture of earth that has suitable proportions of sand and gravel. When the process is complete it is much like constructing a hand made wall of solid rock. Rammed Earth has an excellent thermal mass. This evens out daily temperature variations and reduces the need for heating and cooling. Rammed Earth is environmentally friendly. Using local earth reduces the carbon footprint of the building process.
The colour of the finished wall will vary slightly depending upon where the earth is sourced, as seen in the accompanying pictures. Rammed Earth costs about the same as building with double brick.