Compressed Earth Blocks: A Summary
Non toxic, environmentally friendly, renewable,
soundproof, bug proof, fire proof, even bullet proof!
Compressed Earth Blocks (CEBs) are an incredible
building material.
CEBs take many
forms, these are just one example!
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. 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 of the global south.
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.
Earthblock FAQ
Q: What are Compressed Earth Blocks?
A: Soil! Or rather, soil which has some clay content,
ideally, 12% - 25% clay. Soil with higher clay content
can be mixed with sand or sandier soil to get a
successful mix. The soil is frequently obtained from the
ground at the building site. Roughly 65% of the soil on
the planet can be used to make CEBs – and it can be
found in many locations.
Q:
How are Compressed Earth Blocks made?
A: Production of CEBs can be ahieved manually or
mechanized. The basic procedure is:
The soil (the “qualified” soil with some clay content)
is broken up and larger granules of soil, sand and
gravel are removed by sifting through 1/4" to 3/8" inch
wire screen.
This dry, screened soil and sand (if necessary) are
then mixed well, adding 4% - 10% lime and/or cement to
the mix if you are making stabilized blocks (CSEB). The
mixing can be done by hand with shovels and rakes or by
larger machinery, adding just enough moisture to the mix
to achieve a 10% - 12% moisture content.
The soil is compressed and molded into uniform blocks in
a hand-operated press or a mechanized hydraulic press,
stacked, covered and cured for 1 month.
Q: What is the difference between stabilized and
unstabilized earthblocks?
A: A CEB is stabilized by adding a small amount of lime
and/or cement to the soil with some clay content. The
lime, with the small amount of moisture, chemically
combines with the clay, essentially turning back into
limestone, locking in the sand and gravel to form a CSEB
which is water resistant. CSEBs are more expensive than
CEBs because of the cost of the stabilizer. Unstabilized
CEBs are typically protected by roof overhangs and by
coating the outside of the structure with a lime plaster.
Q: Why would you want to build with EarthBlocks rather
than concrete?
A: First: COST. CEBs are significantly less expensive
than concrete because the materials are locally
available (thus eliminating or greatly reducing both
material and transportation costs). It is cheaper to
stabilize CEBs with a small amount of lime and/or cement
or to protect unstabilized CEBs with lime and/or clay
plasters than to build with concrete blocks or wood.
Q: Are there other advantages to Earth Block homes?
A: A CEB building is not only healthy for the
individual, but also for the planet. Soil, a CEBs
primary ingredient, is a renewable, non-toxic natural
resource. Requiring less transportation of materials,
CEBs have a lower embodied energy than conventional
building materials. It takes many times more energy to
make concrete than it does to make comparable amounts of
CEBs. Cement is made under extremely high heat and the
pollution from manufacture of cement is a major
contributor to global warming. Using wood for buildings
or to fire bricks contributes to deforestation, which is
a significant problem in much of the developing world.
In addition to being good for the environment, energy
savings are immediate because the thermal mass
properties of CEBs results in lower heating and cooling
requirements.
Q: How long does it take to build an EarthBlock home?
A: It depends on the actual size, but a small home
requires 5,000 CEBs and the hand-operated press can
produce 100 CEBs per hour or about 800 CEBs per day,
with a work crew of seven people. Therefore, with one
hand press it would be possible to produce the CEBs for
a house in a week. The actual construction time will
depend on the size and experience of the crew, but
efficiency can be maximized by training in the use of
construction systems such as story poles and thin slurry.
Q: Are these structures strong?
A: Yes, both stabilized and unstabilized CEBs are
appropriate for buildings and meet U.S. building code
standards for compression and modulus of rupture tests.
The durability of a CEB building will allow it to last
for centuries! Ancient earthen structures still stand
today in many parts of the world. The expected life span
of a wood frame building is just 70 years. CEBs have
proven to be waterproof, fireproof, bug proof and
bulletproof, and with bamboo or rebar reinforcement,
these structures can be built to resist earthquake
damage in seismic zones.CEBs) are an incredible building
material.