Factory construction

Types of building materials
Many types of construction are used in today’s buildings. For industrial use, however, the most popular are wood-frame, bricks, slow-burning mill, steel frame, reinforced concrete (RCC) and pre-cast concrete. The considerations in the choice of a particular type are availability, strength, durability, safety and cost.

A wood-frame building may be constructed quickly and cheaply. But it is seldom used for industrial buildings because of its rapid depreciation and high insurance cost and because it is least resistant to fire. Also known as “matchbox construction�, the wood-frame is used in temporary buildings.

If good bricks are available at reasonable rates and excessive strength is not required, buildings may be constructed with bricks made of mud or cement, depending on specific requirements. Brick buildings depreciate more slowly than wood, and alterations in them can be effected with relative ease.

In a slow-burning type construction, bricks and heavy timber are used. A fire takes a longer time to spread through the building because of heavy timber used in it. It can be controlled before it assumes menacing proportions. Despite its reduced insurance cost, this type of construction is rarely used, because it has been largely superseded by modern types of construction.

A steel-frame structure is made up of steel girders, columns, and roof trusses, with spaces between columns which are filled by bricks, tiles or some other material. Alterations can be effected easily and quickly. Insurances rates of such buildings are low. Their disadvantages are: high maintenance cost because of the need for frequent painting, adverse reaction in chemical industries, warping and twisting in the event of a fire, and high depreciation.

Reinforced cement concrete (RCC) is one of the most popular types of construction today, particularly for multi-storey buildings. In this type, a steel frame is encased in concrete, thereby reinforcing it. Both the floors and their supporting columns are made of concrete reinforced with steel. However, the side and interior walls are often of brick, sheet metal or hollow tiles. These walls are merely curtain walls and give no structural support. The ceilings have concrete surfaces.

RCC has many advantages i.e. it depreciates more slowly and its insurance is less because of fire hazards. It is durable and can be easily maintained. Such buildings may be insulated against vibration, which can be reduced to the minimum. They are quickly constructed, and there is a saving in steel, which is scare and costly these days. Their disadvantages are: physical strain to the workmen when they walk on plain concrete floor and too much noise made by the transportation equipment used for the movement of materials. A provision for expansion should be made before construction starts, otherwise alterations and expansion will both be difficult and expensive.

Pre-stressed concrete slabs are increasingly used nowadays particularly in the construction of single –storey buildings. One type of pre-cast concrete is the tilt-up construction, in which concrete walls are poured flat on the grounds and later raised to their vertical positions. Thus, a wall is poured into a frame on the ground to fit a particular wall space. After the concrete has set, it is tilted into position by mechanical means.

Lift-slab is another type of pre-cast construction. In this case, the roof and floors are poured on the ground; after the cement sets, they are hoisted into place and fastened to supporting steel columns. The use of pre-fabricated slabs considerably reduces construction time. The only time-consuming process is to get the slabs ready.