Human Settlements Review - Parliamentary Monitoring Group

Human Settlements Review, Volume 1, Number 1, 2010
of buildings. The inventor of the machine
(Hydraform) in Windhoek estimated that about
80% of all soils in Namibia are suitable for the
usage as stablised soil blocks. For the HRDC
materials from a farm dam and the leftovers
of road construction projects (fines) were
used. For the first phase, the blocks used for
the offices has a cement content of around
4-6%, whereas for the much higher walls at
the public wing (library, conference room)
about 6-8% were added. After the first blocks
were manufactured on site during a fairly
cold month of August, the tests after 28 days
showed low compressive strengths, which was
less than what was required. The curing period
was extended and once the temperatures got
higher, the compressive strength of the blocks
was up to standard. Other wall materials
include rammed earth walls for the exhibition
hall, burned clay bricks, old tyres, sand bags,
dry stone walls made from mica and building
rubble from a demolished municipal flat
building.
Clay has been utilised in various ways
varying from burned bricks to adobe. Some
foundations and walls were built with burned
bricks from Namibian factories, which stated
operations during the time when the HRDC
constriction started. Good quality clay does not
require any additions in adobe construction.
Reinforcement such as straw or grass can
be added. For the construction of one of the
ablution blocks, sand bags constituted the
foundation and reinforced clay balls were
formed by hand are then used to build the
walls by twisting them to form a solid mass.
Hydraform blocks also contain some clay.
Several walls and buildings were built entirely
from old tyres, e.g. storerooms and a double
garage. Several retaining walls were also
constructed with tyres. The idea came from
the USA, where buildings, constructed with
tyres, are called Earthships. The concept
was developed by Michael Reynolds near
Taos, New Mexico, where communities of
earthships have established themselves
(GreenHomeBuilding.com, no date). The
original design incorporates passive solar
architecture, but also have built-in systems
to take into account human needs (Ehrhardt
2000:26). They use the planets natural
systems to provide all utilities - using the sun’s
energy and rain to provide heat, power and
water. They are buildings that heat and cool
themselves, harvest their own water and use
plants to treat their sewage (Low Carbon
Trust, no date).
The German Technical Development
Cooperation (GTZ) provided funding for
building material research, in particular
lime based materials, to assess geological
resources, properties and the economic
viability of products. Calcretes suitable for
building purposes are widely distributed in
the northern and eastern parts of Namibia
(Epukiro), which were utilised from the end
of the 19th century as dimension stones in
several locations. These soft calcretes allow
the artisanal shaping of building blocks with
simple means, e.g. a panga. The extraction of
these materials and the shaping of dimension
stones are labour intensive and yield low
recovery rates (GTZ, BGR, GSN & HRDC
2008:5-6). Once the research was completed,
blocks were transported from the eastern part
of Namibia to Windhoek.
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