Building with earth - Gernot MINKE (1)

9Wet loam infill in skeleton structures
9.1
Plastic loam has been used for thousands of
years to fill gaps in log houses where the
logs are laid horizontally, as well as in palisades
(where the tree trunks are positioned
vertically). In traditional European Fachwerk
(timber-framed) houses, as well as in American,
African and Asian wattle-and-daub
structures, wet loam (usually containing cut
straw) is thrown on an interwoven mesh of
twigs, branches, bamboo sticks and the like
(9.1). As shown in this chapter, there exist
many variations of this technique. Modern
techniques of infill that use mechanical
devices to reduce labour input are described
in this chapter.
Thrown loam
bareque or quincha in Spanish and lehmbewurf
in German.
Such structures consist of vertical and horizontal
members that form a network. European
systems usually employ vertical timber
members interwoven with twigs (9.4).
Loam, usually mixed with cut straw, and
sometimes with fibres, is thrown or pressed
onto this network so that it covers at least
2 cm of all the members. If this cover is not
thick enough and cracks are not wellrepaired,
walls quickly deteriorate (9.3).
The consistency of the mortar being used
is easily checked by dropping a 10 cm diameter
ball from a height of 1 m onto a hard
surface. If the diameter of the flattened disc
thus formed measures 13 to 14 cm, the
consistency is just right.
Illustrations 9.2 and 9.5 show a variation of
the wattle-and-daub technique in which
the size of the mesh is larger (up to 20 cm
apart), and there is an exterior and an
interior network. The spaces in the grid thus
formed are filled in with clods of loam.
Coarse gravel or even stones are sometimes
also used as infill. The type of wall shown in
9.5 is constructed of prefabricated components,
and was used in several low-cost
housing projects in Bahia, Brazil.
9.2
Thrown loam techniques have been used
in all tropical, sub-tropical and moderate
climates of the world, and are probably
older than rammed earth and earth block
practices. These wattle-and-daub techniques
are called bahareque, bajareque,
Sprayed loam
Since wattle-and-daub techniques are very
labour-intensive, various attempts have been
made to use spraying machines to apply
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Wet loam infill