Igloo type brick kilns in Zimbabwe
Practical Action
Construction aspects
The diameters of
igloo kilns vary from
5 to 10 metres, with
capacities varying
from 20,000 to
35,000 bricks per
cycle.
The igloo kiln wall is
normally a massive
structure being about
four brick lengths in
thickness for insulation
purposes. The footing is
executed using either
concrete ordinary brickwork.
Alternatively, the footing
can be made as an integral
part of the bottom slab
executed from ordinary
bricks.
Side flue channels are
inclined into the main flue
channel to allow for
drainage.
For the construction of the
kiln, use is made of either
strong common bricks or
industrial bricks. In some
cases, refractory bricks are
used for the lining. For the
mortar, either clay mortar or
refractory cement mortar is
used. In some instances,
the clay mortar is blended
with ordinary salt,
ostensibly to improve its
strength.
The dome shape of the roof
is formed by the use of
dome bricks or arch bricks
at certain intervals (starting
with the first course of the
roof) during the
construction of the kiln.
Headers form the inside
Figure 2: Plan, section and elevation of an igloo kiln
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