Building with Earth: Design and Technology of a Sustainable Architecture

Unlike other building materials, wet loam

has the capacity to be formed into any

shape. It therefore presents a creative chal-

lenge to designers and builders. The manual

shaping of walls from lumps of wet loam

or thick loam paste is widespread in Africa

and Asia, and is also known in Europe and

America. Since no tools are required to

work with earth, it is the simplest and most

primitive technique. The prepared mixture is

used directly (without intermediate products

being formed or intermediate processes). Its

disadvantage is that even lean loam of only

10% to 15% clay shows linear shrinkage of

3% to 6% when drying. The higher the clay

content and the more water employed,

the greater the shrinkage. Thick loam paste

with high clay content may even have a

linear shrinkage ratio of above 10%. Illustra-

tions 8.1and 8.2show a bench formed

with wet loam elements where shrinkage

was not taken into account. The following

sections explain how pre-designed shrink-

age cracks of smaller dimensions, or the use

of curved elements can help to reduce or

even avoid such cracks. The theory involving

reducing shrinkage by modifying loam com-

position is explained in chapter 4, p. 39.

Traditional wet loam techniques

While in the case of earth block work, dry

elements are built up with mortar joints, no

mortar is used with wet loam work. Plastic

loam is bound simply by ramming, beating,

pressing or throwing.

In southern India, a very simple wet loam

technique is still in use today: using a

hoe, earth is mixed with water to a pasty

consistency, carried to the site in metal

containers balanced on the worker’s head,

and poured on the wall being built. It is

then spread by hand in layers from 2 to

4 cm thick. As the paste dries fairly quickly

in the sun, the wall can be built continuous-

ly, layer by layer.

In northeast Ghana, another technique is

used. Here, balls of wet earth are formed

and then used to construct circular walls

simply by stacking and pressing (8.3 and

8.4). After the wall dries, the surface is plas-

tered on both sides and then smoothed

and polished using flat stones in a rotary

rubbing movement. Illustration 8.5shows

72 Direct forming

8Direct forming with wet loam

8.1Forming a bench

from wet loam

8.2Shrinkage cracks

in the same bench

after drying

8.3 to 8.4Making

walls using balls of

wet earth, northeast

Ghana (after Schreck-

enbach, no date)

8.5Nankansi court-

yard house, north

Ghana

8.1

8.2