Rammed Earth is similar to adobe in its composition, but it is made by compressing moist, not wet earth into a stable form. The resulting brick is several times as strong as adobe and the consistency of the blocks can be very precise. Blocks are made with a press, and all sorts of configurations are available depending on the type of block desired.

The starting point with Compressed Earth Blocks, or CEBs is the soil. CEBs require a proper mixture of a binder and aggregate for strength, similar to concrete. The binder in this case is usually clay, the aggregate sand, and some sort of stabilizer, like lime or Portland cement is used to give the bricks added durability. A simple soil composition test can be done with a clear jar and some water. Fill the jar half way with soil, then add water to the top. Add a few spoon fulls of salt to help with the separation. Shake the jar vigorously, and then set it down and allow the contents to settle for an hour or two. Once the contents have settled, you will see specific layers form. The bottom layer will be your aggregate, then your clay/silt layer, and finally the organic material will be on top. You want about 15-40% clay/silt to 60-85% sand. Little to no organic matter is best.

Once you have chosen your soil, you will need a press. You can either make a hand-operated press that can output 1-3 bricks a minute with three people, or you can make a fancy hydraulic version that can output 6 bricks a minute and can be mostly automatic in its operation. Cost will be a big issue, especially if you are just building one house or a room. Plans are available online, and you can even purchase premade presses.

Forms are needed to determine the dimensions of your bricks. Make your form an even division of the dimensions of your room. Or, make your room an even multiplication of your brick. The nicest size is 6 inches wide, 12 inches long and 4 to 6 inches thick. You will want a form for half and ¾ bricks as well, so you can avoid having to cut bricks. Bricks can also be made for your foundation, lintel, and bond beam, to be filled with reinforced concrete. This is a great method to totally build a building with a simple press and a hand full of forms.

Once made, the bricks can be either laid in mortar or dry-stacked and surface bonded, depending on the design of the structure. Dry stacking is quick, and if you designed your forms to be an even division of the wall, the walls of the house can go up in a few days, or even a few hours with a decent crew.

CEBs are once of the cheapest, simplest building methods available. They are an advancement on adobe blocks and are far more versatile, durable and strong.

To view full directions on how to build a CEB floor, click here.