The idea of man-made covering or shelter dawned when man observed the branches extended from the tree-trunk to shelter them as they rested under its shade after a long journey or hunting trip. Foundations were never thought of until the heavy winds lifted the entire dwelling from its position; it was then the idea of the root structuring anchoring itself into the ground was conceived to keep the trunk of the tree fixed and stable. This structure was patterned and designed for what we know as a foundation for structures. Meanwhile walls were sticks woven into thatched branches to form a ‘screen’. Observing that light, ventilation, entrance and exit were an important factor to the health and safety and well-being to themselves and their family, holes were designed in the “walls” conveniently. Dwellings transformed into civilised structures when humans vegan colonising. Building components and materials used today in construction and safety in the construction industry are the focus of the following paragraphs.
The artificial foundation (slab) is part of the structure that is in direct contact with the ground soil. Its purpose is to support the walls (dead loads), columns and roof that bear directly on the soil. Its main purpose is to evenly distribute the load of the super-structure from damage to soil movement caused by swelling and shrinking. If the settlement is not even, it can result in failed foundations, cracked walls, out of placed doors and windows and the evenly collapse building.
In dealing with foundations, it must be noted that concrete is commonly used. Although stone is another preferred material, but found to be very expensive and not easy to work with. Foundations are required to support the “dead loads’ imposed on it, and these loads are transmitted to the ground (soil type) in a way that the pressure will not cause any settlement or movement that will impair the stability of the structure. It should be deep enough to safeguard the building from any swelling shrinking or freezing of the soil and be capable of resisting the attacks of sulphates or other corrosive matter in the soil. There are four main factors that dictate the design of a foundation:
- The type of building
- The nature of the soil and site condition
- The load the foundation is expected to bear
- The expects of the natural elements
There are four types of foundations
- THE STRIP is the commonest type of foundation. This supports up to four of a building on non-sinkable soil as gravel. This foundation is designed with a continuous strip of concrete on the ground for lad-bearing walls, and depths of no more than three feet must be reached in clayey or marshy soils.
- THE PAD is generally an isolated type foundation; it consists of reinforced concrete supporting concrete columns, especially in framed buildings.
- THE RAFT type covers the entire area of the building to be constructed and sometimes beyond. It consist of reinforced concrete and is designed as a raft hence the name.
- THE PILE AND BEAM type foundation is the alternative to the deep strip foundation. It is required when the building must be constructed on marshy or soft clayey soil. This enables the building to be erected on a firm ground below the top soil, and is mainly used in constructing bridges, jetties and desks near or on the water courses.
These are an essential component of a building. Its main purpose is to enclose space, protect the occupants and their property from the external elements as well as to provide privacy. Walls are either load bearing to support the upper floor and roof or non-load bearing to shape rooms or form partitions and divisions. The materials for walls used in the past were sticks and strips woven together and plastered with mud, these can still be seen in under-developed areas. Timber boards and metal sheets are used mainly for temporary or semi permanent building conditions and for buildings where people do not live in. In the design and construction stage of walls, a few functional requirements must be borne in mind.
- Load bearing walls should adequately support the upper the floor, roof and withstand other compressive stresses imposed on them. The height and thickness are also the important considerations.
- Walls must resistant to damp penetration, swelling and shrinking by moisture. Moisture penetration can result in structural deterioration and threaten the health of the occupants of the building. The use of porous material can compromise the integrity of the walls.
- Walls must be sufficiently thermal (heat) insulated from the external hot weather and must prevent condensation from internal heat gain. The introduction of artificial air (air conditioning) and ventilation reduced the need for large opening in the wall.
- Walls should be resistant to fire, by hindering the spread of flames from one room to another. In case of fire walls should not fall apart but bear the load, protect the occupants and preserve the building as long as possible.
These are structures that afford the occupants access from one floor to another. Stairs must not be too shallow, too steep and tedious, making it near impossible and uncomfortable to climb. Consideration in the design of stairs must be given to the occupants who may be aged or less able to climb. A stair, especially, in public buildings should be wide enough for quick exit in cases of emergency and ease of transporting large furniture and large items. Reinforced concrete stairs are popular and favourable in these times because of the structural quality of the concrete; concrete is easier to construct and is resistance to fire and rot.