Did you know – earth – the ground we walk on and grow our crops in is the most abundantly
used building material on the planet? With over three billion people living, working,
learning, playing, and socializing in buildings constructed from materials such as soil, clay,
mud, and cob. Earth material technology has also been studied, improved upon,
and refined for thousands of years. However, building with earth is often associated with
being “poor,” “backward,” and “primitive.” All over the world, industrialization has led to
an abandonment of earth building traditions, replaced by heavy investments into expensive
and fossil fuel dependent materials such as steel and concrete. Earth, on the other hand,
is a material with excellent thermal mass properties and low embodied energy.
♫ ARTiculations intro ♫
In West-Africa, building
with clay or adobe can be traced back thousands of years. The Dogon people of what is today Mali
and northwestern Burkina Faso had developed a highly sophisticated earth building technique
that is now at risk of disappearing due to the ongoing military conflicts. In
Vitruvius’ Ten Books on Architecture, a seminal architectural treatise from classical antiquity,
there is an entire chapter dedicated to mud-brick masonry. Vitruvius saw it as a
material that exemplified what he believed to be the primary qualities of architecture – firmitas
(durability), utilitas (usefulness), and venustas (beauty). The Egyptian architect Hassan Fathy,
known for reviving and improving the techniques of traditional mud construction in Egypt, utilized
the thermodynamic properties of earth to create passively cooled structures on a large, urban
scale. His highly influential book – Architecture for the Poor, demonstrated how mud brick is a low
cost, sustainable, and beautiful material available to essentially everyone on earth.
The reason earth building materials are excellent thermal masses is because they act as natural
“thermal batteries” that absorb heat during the day and slowly release heat at night,
which can maintain comfortable interior temperatures without the need for mechanical
heating and cooling during all seasons. Earth assemblies generally have a high R value,
which means it’s a very insulating material that can lead to lower energy consumption
even when mechanical heating and cooling are used. Earth also requires very little energy
to extract and manufacture and is made of highly recyclable content. At the end of
an earth constructed building’s life, they simply melt back into the ground, which can
be reused to grow vegetation or harnessed in the future for building materials again.
So why has the industrial world largely rejected earth construction? It may be due to the fact that
soil composition differs from region to region, making it difficult to standardize on a large
industrial scale. It is in fact illegal to build with mud-brick in some regions
due to building code regulations. Are those decisions made entirely for safety reasons? Or
were they results of lobbying by industrial material manufacturers not wanting their
businesses to be threatened by such a low-cost, abundantly available, and versatile material?
While mud bricks are not permitted by certain building codes, the use of compressed earth blocks
(CEBs) is often welcomed. CEB was first invented by French architect François Cointeraux in 1803,
when he developed a mechanical press to compact earth into dense blocks. In 1952, Colombian
engineer Raul Ramirez made a critical advancement to CEB technology by inventing a manually operated
machine that is small, portable, and capable of mass production. A critical ingredient of CEB is
mixing a small percentage of cement to stabilize it, resulting in higher material strength and
weather resistance. CEB also requires very little moisture to produce, does not require firing or
curing, can be used straight out the machine, do not shrink or crack, has a smooth surface
which can be left exposed without a finishing overcoat, and it is considered aesthetically
pleasing due to its natural appearance appealing humans’ affinity to biophilic materials.
An innovative example of CEB construction is by the architect Diébédo Francis Kéré,
who employs the use of locally available resources, traditional materials techniques in
consert with modern solutions, and local community participation in the design and building process.
Kéré is from Gando, a small remote village in Burkina Faso, which is a landlocked,
low-income West-African nation with limited natural resources. The nation has also been
experiencing frequent extreme climate events and tremendous political instability in recent years.
There is little to no access to education in Gando. In 1985 Kéré received a scholarship
to study carpentry in Germany and in 1995 he decided to enroll into the architecture program at
Berlin’s Technische Universität (TU). While he was studying at TU, villagers back in Gando asked him
for help with repairing the village’s only school (built after he left), which was at risk of
collapse. In 1998 he established a charity “School Building Blocks for Gando” to raise money for
building a new school, and began working closely with the community on the design. The new primary
school building (completed in 2001) is comprised of three detached rectangular classrooms under
a single inclined roof. The walls are built from compressed earth blocks connected by earth mortar.
Giving people a good education is very important to Francis Kéré, so before I tell your more
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Industrial materials like concrete and steel are hard to come by in Gando, and wood is minimally
available due to deforestation. Thus clay is a material widely used for buildings in the region
for the past several hundred years. However it’s often considered a temporary material as
it tends to wash away under heavy rains. Kéré believed in the use of clay because it’s free
and locally available. The reddish earth colour fits organically into the surroundings, and it
has a historical connection with the people. To improve performance, the clay compound was mixed
with about 6% cement to achieve stable and uniform bricks that are more weather resistant. He also
introduced the portable manually-operated press, making it possible to easily produce CEBs onsite.
To address the sweltering hot conditions where temperatures can often get as hot as 45°C (113°F),
Kéré pulled the building’s roof away from the top of the classroom. This results in a stack effect
that creates continuous air circulation by drawing in cool air from the windows,
which rises through the perforated clay ceiling, and vents out the perimeter gap below the roof
canopy. This design feature alleviates the need for costly and energy intensive air conditioning.
Thus a passively cooled building with a low ecological footprint was created out of necessity.
Francis Kéré’s designs are able to achieve durability, usefulness, and beauty through paying
close attention to the simplest building block of architecture – the material. He also demonstrates
why a deep connection to material culture may be the key to achieving economic independence for
developing African nations, as well as a creating more sustainable future for the rest of the world.
So is Earth, this building material of the past - actually the material of the future? Maybe.
I personally think we should be building with mud and clay a lot more than we currently do,
but it obviously isn’t a solution in every scenario. I think the more important lesson
we should take away from earth construction is a careful consideration of limited resources,
passive building techniques, human factors,
and local cultures. Let me know what you guys think in the comments below.
As always thank you guys so much for watching. I recently decided to go back to school for a masters degree
and this video is actually an adaption of one of my assignments. If you enjoyed this video,
feel free to check out more like it right here and I’ll see you guys next time!
*snap*
♫Outro Music ♫
Are these decisions made entirely for safety reasons?
I don’t know. I don’t know the answer to that.