Civil Engineering Reference
In-Depth Information
In Denmark, comprehensive timber recycling is now developing. Old oak
beams are split up after the central core (malmen) has been removed for use in
floor boards or windows. The renewal of timber windows has also become sig-
nificant in the industry.
Old timber has the advantage that, since it is dead, it does not twist, and there-
fore provides good material for floors, for example. Nails and other metal details
which may be part of the timber components can cause problems.
In Belgium and France old quality timber costs about 25-50 per cent of the
price of new timber, while in Holland old timber costs up to 75 per cent of the
price of new.
Grasses and other small plants
Plants mainly of the grass species produce straw which often has a high cellulose
and air content, making it strong, durable and well-suited for use as insulation
material.
Species such as rye, wheat and flax also contain natural glues and can be com-
pressed into building sheets without additives. Elephant grass is a large grass plant
first imported to Europe from Asia in 1953. It produces large quantities of grass straw
well suited to building sheets. These plants can also be used as reinforcement for tra-
ditional earth structures and as roof covering. The cleaned plant fibres of flax, hemp
and, stinging nettles can be woven into linen, carpets, wall coverings and rope.
Peat and moss have always been used to seal joints between materials and
between different parts of buildings, e.g. as the sealant between the logs in log
Table 10.8:
The use of plants in building
Plants
Part used
Areas of use
Location
Cultivated plants:
Wheat (
Triticum
)
Stalk
Roofing, external cladding,
building boards, thermal
insulation, reinforcement in earth
and concrete
Roofing, external cladding,
building boards, thermal
insulation, reinforcement in earth
and concrete, woven wallpaper
Roofing, external cladding,
building boards, thermal
insulation, reinforcement in earth
and concrete, rope and woven
wallpaper
Oil
Northern Europe
Rye (
Secale cereale
)
Stalk
Northern Europe
Flax (
Linum
)
Stalk
Northern Europe
Seed
continued overleaf
