First, it is important to understand that timber is not a name of a specific type of wood. Timber is an any type of wood which has been processed into beams and planks. Timber means wood which is suitable for building carpentry and for various engineering and other purposes. The word timber is derived from an old English word ‘timbrical’ which means to build. Timber or wood as a building material possesses several valuable properties, such as low heat conductivity, amenability to mechanical working, low bulk density and relatively high strength.
Types of timber and their role in civil engineering:
In general, timber is divided into two major categories, hardwood and softwood, depending upon the strength and hardness of wood. These categories contain many types of timber, the important types as well as their role in construction are discussed below:
Bamboo is a natural organic material. It is one of the most unique plants on earth. It is one of the strongest and yet cheap. Bamboo is easy to grow and cutting of bamboo is not a major threat to environment. Although bamboo has been identified as the most promising building material for decades; technical, normative, and cultural challenges have prevented its widespread use in construction. An increase in the use of bamboo in construction could lead to energy savings, conservation of the world’s scarce resources and reduction in environmental pollution.
Birch is a great craft-wood. It is an important source of hardwood timber. Birch is of many types e.g. yellowish birch, white birch etc. Birch is particularly common in the northern hemisphere, in cold climate. This hard, heavy wood is economical, long lasting with a brilliant aromatic gift. Birch is suitable for high-quality furniture and plywood. Due to its strength and lightness, birch is also good at supporting large structures. The most prolific example of this was during the Second World War when the United States built the largest flying boat ever and the aircraft with the largest wingspan in history, the Spruce Goose.
One of the best types of timber. It comes from different types of trees and gives both strengths and looks. On the plus side, it is workable. It is light weight and its weather resistance makes it suitable for construction purpose. Cedar has long-time durability and has exceptional resistance to insects and decay. It can also be used as sound proofing in construction.
Cherry timber is one of the most loved in eastern nations. It has medium density and moderate durability. It is used for small pieces of furniture’s-veneers, handles, cabinets, scientific instruments etc. It also becomes darker and richer with age, so construction rather increases in aesthetic sense as time wears it out. It can be used in flooring, and as well as making doors and windows. However, to get this brilliant timber, you must have a heavy pocket.
Cross laminated engineered timber systems and Glued laminated timber, challenge steel and concrete in relation to spans and strength utilising spruce, pine or larch and stand up to corrosive environments such as swimming pools in a way that cannot be matched. It is manufactured in panels that have an odd number of softwood plank layers laid on top of each other at right angles and glued together under pressure. Cross-laminated timber panel building systems allow quick erection on site. This is advantageous not only in rural locations, where workforces can be limited, but in urban areas as well, where it is important to reduce noise and disruption.
The softer Mahogany is a high-quality timber. It is grown commercially almost in every continent. Mahogany is widely used in the furniture and cabinet building industry. Its quality to bend without splintering or shattering makes it extremely useful for certain construction processes. But for now, it is not that common is construction industry.
Oak is used in light construction more often than any other wood. It is considered to be the traditional carving wood, oak is characterised by its strength and sturdiness, with a very defined grain. It is very strong, but at same time it takes glues, nails, and screws well, making it perfect for construction of interior parts. However, it is not suitable for external use in buildings because of environmental effects.
Plywood is an engineered sheet timber product that is widely used for construction purposes. It is manufactured from three or more thin layers of wood veneer, or ‘plies’, that are glued together to form a thicker, flat sheet. Plywood is manufactured from softwoods (such as Douglas fir, pine, and redwood), hardwoods (such as ash, maple, and mahogany), or a combination of both. High strength, moisture resistance, chemical stability, and flexibility makes it the favourite of civil engineers.