Building with earth - Gernot MINKE (1)

14.26 14.27
property of the salt, this loam stays moist
for longer periods, and prevents water
penetration while it remains in this state.
If shrinkage cracks occur during drying,
swelling occurs during contact with rain
and seals the cracks. Once the rain has
washed off some of the salt, reducing the
self-sealing effect of the top coarse layer,
residents can either sprinkle salt or pour
salt water on it to regenerate the seal
(Dalokay, 1969).
When making loam-covered flat roofs, it
should be kept in mind that roof edges are
susceptible to mechanical damage, especially
by wind and water erosion. This can be
prevented by solutions of the type shown in
14.27. If the surface of the roof is to be
walked upon, then tiles are recommended
(14.27 D).
Illustration 14.26 shows an inclined roof
from northern Venezuela, consisting of layers
of cow dung stabilised with straw loam
mortar applied in several layers (8 to 12 cm),
over a wooden substructure made of
branches and twigs. After the rainy season,
the top layer is normally redone.
have proved that additives can increase
the weather resistance of loam.
Bases on test results of the BRL, described
in chapter 4, p. 40, a low-cost housing
prototype was built at Pujili, Ecuador, by the
group FUNHABIT, Quito, and the author.
The roof was made of a timber substructure
built of tree trunks, branches and reeds. This
was covered by several layers of loam plaster
that were 8 cm thick in total (14.28). The
first layer consists of clayey loam thinned
with pumice (0 to 12 mm diameter) and
waste mobil oil (52 parts loam : 28 parts
pumice : 1 part oil). This mixture, which also
provided thermal insulation, was laid in a
fairly dry consistency and compacted by
beating. The top layer, 2 to 3 cm thick, has
the following mix: 72 parts loam, 36 parts
pumice (0 to 5 mm), 12 parts cow dung,
12 parts donkey dung, 8.5 parts mobil oil,
6 parts loose Sisal fibres (3 to 5 cm long),
and 1 part double-boiled linseed oil. After
several days, when the mixture was somewhat
dry, it was recompacted with a metal
trowel, using great pressure, till the surface
was shiny.
14.26 Traditional loam
roof, north Venezuela
14.27 Traditional flat
loam roofs
14.28 Vertical section
through a loam roof, Pujili,
Ecuador
14.29 Earth block domes,
village near Aleppo, Syria
14.30 Earth block domes,
Siestan, Afghanistan
14.28
New solutions
In rainy areas, where inclined roofs are
common, traditional buildings do not have
loam roofs. However, recent experiments
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Designs of building elements