Building with Earth

Think of rammed earth as a sort of "instant rock". The natural process of creating sedimentary rock occurs over a span of thousands and millions of years. An earth rammer, on the other hand, creates it in a matter of minutes. - David Easton - The Rammed Earth House.

Working with earth is simple in one sense, but very complex in another. Soil is so diverse, its properties and reactions so widely variable, that to fully understand its uses and limitations, and to build with it successfully, takes years of study and experience. - David Easton - The Rammed Earth House.
Rammed Earth homes
Advantages:-

1. uses local materials, reducing our impact on the planet.
2. Reduces the demand for lumber, protecting the Forests.
3. Rammed Earth homes can be extremely attractive cue to flexibility of shapes.
4. lend themselves to passive solar design.
5. These are energy efficient - reducing our dependance on fossil fuels, which reduces air pollution and other impacts associated with fossil fuels.
6. Can be built with wide variety of styles, contemporary, classical, southwestern etc
7. Walls are very strong and capable of resisting earthquakes, tornadoes, hurricanes
8. walls are resistant to decay and are safe in fires. In fact, fire hardens and strengthens the exterior walls.
9. Thick Walls of rammed earth are soundproof, a benefit of immense value in today's noisy world.
   
10. Walls are also impenetrable to insects and rodents.
11. Less expensive technology than brick, stone, adobe or even ferro-cement construction.

Disadvantages :-

1. Fairly labor intensive construction and can be costly than other types where the labor charges are high.
2. building walls, takes a long time and is a hard work.
3. Requires careful analysis of soil, without that costly errors can occur.
4. On-site mixing, wetting and compacting of soil requires proper attention. Error made will be irreversible once the walls are hardened.
5. Requires special skills.
6. Lot of wood required for form work, although some can be reused.

Cast earth Construction :- This is an alternative to rammed earth. In this, a slurry of sand, gypsum and water are poured into concrete forms. This accelerates the wall-building process reducing the time and cost factors.

According to Cast Earth affiliates :- Cast Earth has been demonstrated successfully in actual residences. It is a true "breakthrough technology", providing a product with all of the properties of traditional earth construction, augmented by superior aesthetics, rapid construction, and affordable cost.


Wall strength usually ranges from 600 to 700 pounds per sq. inch same as high quality adobe & rammed earth but has almost 1/2 to 3/4 of their labor cost.

Since its free flowing slurry and quick to set up, the forms can be lightweight and flexible in shape. Gypsum counteracts the clay tendency to expand and contract depending on moisture level, thus reducing the cracking.

These Thick mass walls are ideal for passive solar heating and passive cooling, thus reducing the lifetime cost for maintenance and energy.

Cast earth is more resistant to rain than rammed earth and adobe. If unprotected, it will absorb rain but will retain its original wet strength. r proofing can be added to the slurry or applied to outer wall. Like rammed earth, cast earth walls can be insulated. Rigid insulation can be inserted in forms prior to pouring the slurry.

Since the technology is machinery intensive and requires extensive form work, this lends itself to mass production.