Compressed Earth Block (CEB) Basics
Compressed Earth Block, Earth Block, or CEB is a construction material made from the dirt beneath your feet to build a wide variety of structures including homes, schools, churches, clinics, stores, barricades and fortifications. Compressed Earth Blocks are made by compressing a soil and 6-10% Portland cement (used as a stabilizer) in a Smiley CEB press. These blocks can be used to build with after curing for 14 – 21days. They reach full strength and become water resistant after a 28-day cure period. There are numerous reasons to build with Earth Block. In addition to the fact that an estimated 2 billion or 30% of the earth’s population live in earthen structures, Earth Block Structures are:
- Provide a nice place to live and work
- Earth Block structures are warm, solid, and quiet. It has been described as having a warm comfortable blanket wrapped around you.
- Environmentally sound
- Earth Block structures can use up to 20 to 30% less energy to heat and cool than concrete block or wood frame structures.
- Dirt is a renewable resource that is plentiful.
- Earth Blocks take very little energy to make compared to the extreme heat necessary to make cement, the firing process required to make bricks, and the deforestation required to build with wood.
- Earth Block walls are sound proof, fire proof, bullet proof, bug proof, and mold proof.
- Use materials available locally
- Materials to make earth blocks are plentiful and can often be found locally reducing transportation costs and environmental impact. Earth blocks can often be made at the construction site which eliminates the need to transport the materials required to build the walls.
- Since the blocks are made from natural material they do not out-gas any toxic chemicals.
- Long lasting
- Earthen homes have been around for thousands of years. Earth Blocks will last for centuries. Average life of a wood frame building is 70 years.
Compressed Earth Block Construction
CEB’s can be used in place of conventional masonry products in many types of applications including:
- Dwellings – from low cost to upscale
- Public buildings, including schools, churches, clinics, etc.
- Commercial and industrial buildings
- Military applications such as barricades, fortifications, and security walls
- Walls and linings for canals, dams, drains, and erosion protection
- Storage facilities for waste and toxic materials
- Mining applications
- Disaster relief
The Compressed Earth Block designed by Desmond Elliott is made using a Smiley CEB Press is called the “Lego style” Block. The Lego style Block is uniform in all three dimensions. It has a unique interlocking design which allows it to be dry stacked or motared and does not require traditional labor intensive skill associated with masonary construction. If requested, the blocks may be bound together with a thin slurry made from same material as the blocks. Like substances bond making the wall a monolithic structure. All of these features make for a much more economical wall system. Walls can be built, much faster than conventional masonry, with unskilled labor while under the supervision of someone who is familiar with basic construction techniques. A lateral strengthening layer is added every one metre in height. This is achieved using the channel infill plate to the press. In the channel two lateral reinforcing rods are laid and filled with concrete.
A Lego Block is 15cm X 30 cm X 10 cm (6” X 12” X 4”)
Click here to see a Video of the build.
A wall 2.5 meters (8 feet) high and 9.3 meters (30 feet) long would take approximately 1200 Lego Blocks.
A Compressed Earth Block wall requires at least 25 cm (10”) thick and 33% wider than the wall width. For multiple story buildings the area bearing the weight of the wall would be built according to the specifications provided in the documentation.. For single story dwellings a concrete slab 4′ (10 cm) think can be poured. The slab is an ideal surface to manufacture the bricks. The Compressed Earth Bricks when made to recommended specifications can be used in two and three story buildings without the need for a reinforced concrete skeleton. However, local building codes should be adhered to to satisfy authorities.
A Lego Block weighs approximately 22 – 25 lbs. A cubic yard of soil weighs approximately 2,600 lbs. So you can make approximately 118 – 104 Lego Blocks per yard of soil. A 30 square meter structure would require approximately 12 yards of soil to construct. The voids in the Lego Blocks reduce the required soil by 30% compared to other solid Compressed Earth Blocks.
Finishing and Waterproofing
Compressed Earth Block walls can be painted using cementious paint or clear coat. Both inner and outer walls can also be covered with plaster, using a wire lathe which has the additional benefit of adding strength to the wall system. There are also several natural plastering methods that can be applied.
Shake table tests have shown Compressed Earth Block walls built with steel reinforcements offer superior seismic performance. Additionally, Lego Blocks were designed so vertical and horizontal reinforcement can be integrated into the wall system design essentially creating a steel basket within the wall system. In earthquake prone areas the lateral reinforcing layers can be added as often as required to meet local engineering requirements.
CEB’s can save up to 30% compared to traditional masonry construction. This is achieved by using readily available materials (soil) and reduced labor costs for wall construction. You also have the benefit of a superior quality structure with far less environmental impact.
The CEB building system is an Open Source project sponsored by and recommended by the United Nations. A complete engineering specification has been prepared for international use. A PDF file setting out the testing and strength analysis are documented to satisfy local engineer requirements. PDF Documentation of shear and laboratory destruction testing is available for engineering and application compliance. To download a White Paper (INTERLOCKING COMPRESSED EARTH BLOCK)