Building with earth - Gernot MINKE (1)

5.28
5.26
Plaster
Soil blocks
Thermal insulation
Lightweight loam
Soil blocks
Bricks
Lightweight loam
Thermal insulation
Mud plaster
Rammed earth domes
Probably the first rammed earth dome was
built by the BRL in Kassel, Germany, in
1983 using a special technique developed
by that laboratory. This consists of a rotating
slip form in which the earth is rammed
(5.31, 5.32, 5.33).
The thickness of the dome was 18 cm at
the bottom and 12 cm at the top. The walls,
which form a hexagon on the inside, were
also made of rammed earth. In order to
transfer the thrust from the dome to the
foundation, buttresses were integrated with
the walls. The shaping of the top of the buttresses
as well as the windows was done
with a kitchen knife soon after the form-
5.27
work was dismantled. The formwork of the
wall was custom-designed according to the
plan of the dome, as seen in 5.31. The earth
was rammed into the formwork using a
vibrator, described on p. 55 in this chapter
(see 5.12), and by hand.
The dome formwork itself was so designed
that it could be lifted not just at the centre,
course after course; it also had a guide that
automatically adjusted the radius and inclination
of the formwork (5.33).
Drying
It is seldom possible to say when a loam
wall is dry, but the drying process is in any
case faster than those of masonry or concrete
walls (see chapter 2, p. 28). Given dry
warm weather and sufficient air movement,
shrinkage stops after just a few days. After
three weeks, the wall feels completely dry,
although water content is still slightly higher
than the equilibrium moisture content.
Plaster
Thermal insulation
Lightweight loam
Lightweight loam board
Mud plaster
Timber panels
Protection layer
Thermal insulation
Lightweight loam
Gypsum board
5.30
59
Rammed earthworks