Building with earth - Gernot MINKE (1)

10 Tamped, poured or pumped lightweight loam
Formwork
Lightweight loam walls can be constructed
using any type of formwork, but since less
impact is involved than with rammed earthwork,
the shuttering boards can be thinner.
Various possibilities are shown in horizontal
section in 10.1.
In order to reduce the number of boards,
climbing formwork is often used. Four
types of this system are illustrated in 10.2.
When working with lightweight mineral
loam, it is even possible to use only a onesided
formwork. This could be done with
a board on the outside, in which case the
mixture can be thrown onto it from the
inside by hand or with a trowel.
10.2 10.1
Tamped lightweight straw loam walls
10.1 Horizontal sections
with different inbuilt timber
elements
10.2 Systems of climbing
formworks
This chapter introduces several techniques
that use lightweight loam by tamping, pouring
or pumping for floor, wall or roof systems.
The different types of lightweight
loams are examined in chapter 4, while
chapter 9 discusses how lightweight loam
can be used as infill for timber-framed and
skeleton structures. Sprayed plasterwork is
described in chapter 11. Special designs for
walls which give high insulation are discussed
in chapter 14, and additional thermal
insulation measures using lightweight loam
are addressed in chapter 13.
The preparation of the mix is described in
chapter 4, p. 46. The mixture is thrown into
the formwork in layers 10 to 20 cm in height
either by hand or (more usually) with a
pitchfork, and compacted with lightweight
hand tampers.
It should be mentioned that lightweight
loam mixtures tend to settle, so that the
gaps that form must be be inspected and
later refilled. The one-metre-high test element
shown in 10.3 displayed settling of
9%.
It should also be mentioned that when
working with very light mixtures (with densities
below 600 kg/m 3 ) and with walls more
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Tamped lightweight loam