Materials of animal origin - The Ecology of Building Materials - page 180

Table 11.1: Building materials from the animal kingdom

Part Areas of use

Coral The whole coral Building blocks, structures

Bees Wax Surface treatment of wood and hide

Fish Oil/protein Binder in paint and adhesives

Poultry White of the egg Binder in paint and adhesives

Hoofed animals Wool (sheep/goat) Textiles, wool-based sheeting, sealing around doors and

windows, thermal insulation

Hair (horse, pig, cow) Reinforcement in render and earth floors

Hides and skins Internal cladding, floor covering, boiled protein used as

binder in paint and adhesives

Bone tissue Boiled protein used as binder in paint and adhesives, ash

used as pigment (ivory black)

Blood Protein substances used as binder in paint and adhesives,

colour pigment

Milk casein Binder in paint, adhesives and fillers, base material for

casein plastic

Lactic acid Impregnation

Products from the animal world have a limited use in modern building.
Sheep's wool is useful for carpets, wallpapers, paper and more recently as ther-
mal insulation and for sealing of joints. Wool of lower quality which would oth-
erwise be wasted can be used for insulation and joint sealing. Beeswax has
become a popular substance for treating timber surfaces. Protein substances
extracted from milk, blood or tissues are still used as binding agents for paint
and glue. Animal glue is the oldest known, and was used in ancient Egypt.
Traditional animal glue is produced by boiling skin and bone to a brown sub-
stance. When it is cleaned, gelatine, which is also used in the food industry, is
obtained. Casein glue is made from milk casein, produced from curdled milk by
adding rennet, and has a casein content of 11 per cent. Casein contains more than
20 different amino-acids and is a very complex chemical substance, but has no
binding power in itself. Lime or another alkyd must be added to make the casein
soluble in water. Casein plastic is produced from milk casein by heating the
casein molecules with formaldehyde (HCHO) under pressure. This plastic, also
called synthetic bone, is sometimes used for door handles.
When lactic sugar ferments, lactic acid (C 2 H 4 OHCOOH) is produced, which is
a mild disinfectant.
In the south, a future can be envisaged in which organisms from the ocean
such as coral (which depends upon warm water for quick growth) will be used
in manufacturing building components. On tropical coasts this has considerable
moral implications - as poisons may have to be used to hinder growth and pro-
duce the right dimensions.