Compressed earth block

Compressed Earth Block often referred to simply as CEB, is a type

of manufactured construction material formed in a mechanical press

that forms an appropriate mix of dirt, non-expansive clay, and an

aggregate into a compressed block. Creating CEBs differs from

rammed earth in that the latter uses a larger formwork into which earth

is poured and tamped down, creating larger forms such as a whole

wall or more at one time.

CEB blocks are installed onto the wall by hand and slurry made of a

soupy version of the same dirt/clay mix, without aggregate, is spread

or brushed very thinly between the blocks for bonding. There is no use

of mortar in the traditional sense.

Building a CEB project in Midland, Texas in August 2006

Development of CEB

The advance of CEB into the construction industry has been driven

by manufacturers of the mechanical presses, a small group of eco-

friendly contractors and by cultural acceptance of the medium in

areas where it is seen as superior to adobe.

In the United States, most general contractors building with CEB

are in the Southwestern states: New Mexico Colorado, Arizona,

California, and to a lesser extent in Texas.

However, manufacturers of the mechanical presses enjoy their

heaviest sales overseas. Mexico and Third World countries have

been attractive markets for the presses for years.

Advantages of CEB

The advantages of CEB are:

•CEB can be pressed from humid earth. Because it is not wet, the drying

time is much shorter. Some soil conditions permit the blocks to go

straight from the press onto the wall. A single mechanical press can

produce from 800 to over 5,000 blocks per day, enough to build a 1,200

square feet (110 m2) house in one day.

•Shipping cost: Suitable soils are often available at or near the

construction site. Adobe and CEB are of similar weight, but

distance from a source supply gives CEB an advantage. Also, CEB

can be made available in places where adobe manufacturing

operations are non-existent.

•Uniformity: CEB can be manufactured to a predictable size and

has true flat sides and 90-degree angle edges. This makes design

and costing easier. This also provides the contractor the option of

making the exteriors look like conventional stucco houses.

•Non-toxic: materials are completely natural and do not out-gas

toxic chemicals

•Sound resistant: an important feature in high-density

neighborhoods, residential areas adjacent to industrial zones

•Fire resistant: earthen walls do not burn

•Insect resistant: the walls are solid and very dense, discouraging

insects

•Mold resistant: there is no cellulose material - such as in wood,

Oriented Strand Board or drywall - that can host mold

Thermal advantages

• CEB has excellent thermal performance, reducing heating and

cooling costs.

•Thermal testing: From May 31 to June 3, 2004, the Biology Dept.

of Southwest Texas Junior College, Del Rio, Texas, conducted

tests for thermal change on three structures: concrete block, adobe

and compressed earth block.

•Results indicate the interior temperature of the adobe and CEB

modules were significantly lower than for concrete blocks.

Concrete Module: 111 °F (44 °C)

Adobe Module: 95 °F (35 °C)

CEB Module: 91 °F (33 °C)

Non toxic, environmentally friendly, renewable, soundproof, bug proof, fire

proof, even bullet proof! Compressed Earth Blocks (CEBs) are an

incredible building material.

Compressed earth block (CEB) construction is an earth-friendly building

technology that is superior to concrete and wood construction in terms of its

health benefits, affordability, durability, and energy efficiency.

CEB technology is a contemporary improvement of ancient earth building

methods. SCEBs are made of clay, sand and a small percentage of lime

and/or cement that is compressed by machine.

Compressed Earth Blocks

The benefits of CEB, especially in low-income and marginalized

communities, are many. Suitable soil is abundant and blocks can be

compressed using manually operated or powered presses at a low cost.

The health, comfort and durability of CEB buildings are superior to that of

concrete block or fired brick constructed structures, the predominant

building materials and methods in rural areas.  

Because of their thermal mass, CEB homes naturally provide some

passive heating and cooling, providing increased comfort for it's

inhabitants. This appropriate technology is also environmentally friendly

and transferable to large and small scale applications.

Reliance on forest resources is largely eliminated and energy

consumption in the production of blocks is many times less than that

required for fired brick and concrete.

Dimension of CEB Health

Earth regulates the climate in the house naturally. The compressed

earth blocks are not fired so that the unique moisture-regulating and

heat-accumulating properties are preserved. The wall absorbs

moisture in wet weather and gives it back when the air is dry.

The production process

The compressed earth blocks are produced by a mobile compressing

machine, which is capable of producing blocks for larger projects on site

as long as the building ground is of good quality.

The fertile top soil is temporarily moved aside, the clay-retaining under

layer is dried by the sun and wind and then pulverised. It is then moistened

and mixed with sand depending on the proportion of clay in the earth.

The compressing machine now makes uniform earth blocks from this

mixture which will be ready to be used after a few weeks of drying.

The bulk of the compressed earth blocks means that an earth wall can

storeheat well and give it off again so that temperature fluctuations are

fewer.

Earth emits no hazardous gasses or substances into the interior

atmosphere and in addition neutralises cigarette smoke for example.

The constant relative humidity of approx. 50% in an earth interior climate

prevents fungus forming. That is why an earth house is a "breath of fresh

air" especially for people with problems with their airways