You can build with earth in three ways:
1. Mud brick/ adobe: unbaked bricks (these could be used for walls, vaulting, etc)
2. Soil block: Compressed, unbaked brick
3. Rammed earth: compacted in formwork, could be reinforced with things like bamboo. Monolithic and has some possibility of curved surfaces, probably harder to make roofs out of...
I understand Village Hope has managed to obtain a brick compressing machine, which would be interesting to play around with and experiment. But what we need to do now is figure out the contents of the soil in our site. To take maximum advantage of the natural resources and the sustainability potential of earth, it would be ideal to only use earth excavated from the site itself. However, there earth has to have a good ratio of sand, silt, and clay... the desired mixture should have plenty of the latter. On the other hand, if it has too much clay, sand and gravel might have to be brought in and mixed in.
Apparently some criteria that could be considered when design for earth are:
-High humidity regulation and absorption
-High thermal mass index (to regulate temperature)
-Can be coated to become less permeable
-Lends itself to use of green roofs (look at the funky earth house in Switzerland designed by Peter Vetsch)
-Can build vaults with the bricks (consider methods like Nubian vaulting or Ramon Aguirre's Mexican vaulting that don't require formwork)
