A construction site People have constructed buildings from ancient times as homes to provide shelter, monuments or places of worship. Earth, wood and stone have always been used as building materials. Bricks made from hardened clay were first used in the Middle East in about 3000 BC. Concrete is made by mixing sand, cement, water and gravel or other aggregates. Reinforced concrete dates from the late 1800s. It is often used in modern buildings, containing steel wires or rods to provide extra strength.
Types of buildings
Buildings belong to one of two types. The first type has solid walls, called load-bearing walls, that support the floors and roof of the building. The second type has a framework of wood, steel or concrete that bears the weight of the building. Most buildings need foundations (a solid base) to prevent them from sinking into the ground or falling over. Foundations can be footings (underground walls), flat rafts, or underground supporting pillars, called piles, that are driven into the ground. An architect plans the design of the building, while engineers work out how to make it strong and safe.
Many machines are used in the construction of a tall building. A tower crane is a vital machine. It lifts heavy building materials, such as steel girders and concrete slabs (which form the building's floors and walls) to the upper floors.
Stages in house construction
- Foundations Using a digger and a bulldozer, the builders clear and level the site. They then mark out the foundations before digging trenches. Concrete is poured into the trenches to form the foundations. After the concrete is cured (achieves full strength), the builders fix a waterproofing membrane to the foundations.
- Framed construction… A house may have a framed construction or a mass wall construction. A framed construction involves fitting together lengths of timber to give the structure support and shape. Plywood sheets are fixed to the exterior walls, which are then covered with a protective layer known as house wrap. Exterior finishes or cladding, such as brick or stone, are then added.
- …or masonry wall construction In masonry wall construction, bricks or concrete blocks are bound together with mortar (a mixture of sand, cement and water) to form walls. These are built up to the height of the roof, with openings for windows and doors. The walls support the upper floor and roof. Concrete beams are laid over the top of door and window openings.
- Roof Tiles or panels are fixed to the roof trusses (frame).
- Carpentry Windows, doors and staircase are fitted.
- Plumbing and electrics Electricians and plumbers run wires and pipes through the interior walls, ceilings and floors. Piping is installed for the heating and air conditioning systems.
- Finishing walls and ceiling Insulation is fitted to exterior walls, floors and attic space. Plasterboard (drywall) is fixed to the interior walls and ceilings. Architraves, skirting, interior doors and window sills are fitted.
- Fixtures and fittings Sinks, toilets and taps (faucets) are fitted. Tiles and flooring are installed, along with kitchen worktops. Sockets, light fixtures and switches are fitted. Finishing coats of paint and wallpapering are applied.
- Exterior Exterior driveways, walkways and patios are built.
The drum of the concrete mixer spins round, mixing the ingredients—cement, sand and crushed rock (known as aggregate) and water—together. The concrete mixer keeps the concrete in liquid state by constantly turning the drum. The interior of the drum is fitted with a spiral blade. Rotating the drum in one direction, the concrete is pushed deeper into the drum while the concrete is being transported to the building site. This is called charging the mixer. Rotating the drum in the other direction forces, or discharges, the concrete out of the drum into chutes or into a concrete pump.
and dumper truck
A bulldozer uses its blade to push earth and rubble. A digger (also called a JCB or backhoe loader) can tear into the ground using the “teeth” on its loader bucket or backhoe. It scoops up the rubble and pours it into the back of a dumper truck. To dump its load, the truck body tips up, the tailgate at the back swings open and the rubble slides out.
Many construction vehicles have caterpillar tracks instead of wheels. They provide extra grip and spread the vehicle's weight, allowing it to move over muddy ground without slipping or sinking in.
Consultant: Chris Oxlade
Concrete is first used by the ancient Egyptians, Chinese and Greeks.
The first cranes are used in ancient Greece.
British inventor Richard Edgeworth invents the caterpillar track.
Reinforced concrete is invented by French gardener Joseph Monier.
The first skyscraper, the Home Insurance Building, is built in Chicago, USA.
The first dumper truck is built in Canada by Robert T. Mawhinney.
The first bulldozer is constructed in the USA.