Plants

The forest gives generously the products of its life and protects us all

Pao Li Dung

Until the introduction of steel construction at the beginning of the industrial revolution, timber was the only material with which a complete structural framework could be built. Timber unites qualities such as lightness, strength and elasticity. Compared with its weight, it is 50% stronger than steel. It is more hygienic than other similar materials - the growth of bacteria on kitchen benches of timber is lower than that on benches of plastic or stainless steel. Timber also has low thermal conductivity. On the other hand, the high carbon content of plant materials makes them combustible and more susceptible to biological decay.

However, in relation to most modern European building standards, timber can still be used in up to 95% of the components of a small building. This includes everything from framework and roof covering to thermal insulation and furniture.

There are many non-structural uses for plants from climbing plants that act as a barrier against wind and weather, to linseed oil from the flax plant used in the production of linoleum and various types of paint. Wood tar and colophony can be extracted from wood for use in the

Table 10.1 Use of plant materials in the building industry

Material

Areas of use

Softwood and hardwood

Structures; wall cladding; flooring; roof coverings;

windows and doors; pins and bolts;

thermal insulation; fibres; cellulose; chemicals

Climbing plants

Wall cladding; air cleaning

Straw and grass

Roof covering; wall cladding; thermal insulation; minor structures; cellulose; chemicals

Grass turf

Roof covering; minor structures

Moss

Thermal insulation; joint sealant

Peat turf

Thermal insulation

Peat turf

Thermal insulation

Table 10.2 Basic plant materials

Material

Area of use

Acetic acid

Disinfectant; bioplastics

Cellulose

Thermal insulation; sound insulation; paper products for wind proofing and vapour retarders; wallpapers

Fatty acids

Paints; varnishes; adhesives; soap treatments; bioplastics

Fibre

Thermal insulation; sound insulation; building boards for cladding, underlay, wind proofing, vapour retarders etc.; reinforcement in concretes, plasters and biocomposites; sealing of joints; carpets

Lignin

Adhesives; additive in concretes; bioplastics

Methanol

Adhesives; paints; varnishes; bioplastics

Potash

Glass production; potassium waterglass

Silicates (siliceous plants)

Pozzolana in cements

Starch

Adhesives; paints; bioplastics

Turpentine

Solvent in paints and adhesives

paint industry and pine oil for the production of soap for treatment of wooden floors. Copal is extracted from tropical woods and is used as a varnish. Natural caoutchouc from the rubber tree can be used in its crude form as a water repellent surface treatment. Oil from soya and linseed, starch from potatoes and maize, methanol and cellulose which can be derived from most plants, form a basis for bioplastics that is likely to become more common in the building industry as fossil oils become scarce. Biocomposites are also experiencing a breakthrough; these consist of plant fibres used as fillers and reinforcement in building sheets. The binder is often cement or plastics but bioplastics are also being tried out.

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