Foundations are used to carry the load of a building to the ground. This is the safe soil bearing capacity. The foundation concrete that is reinforced with steel allows buildings to be done more stories upwards. This means the concrete base can take more loads. The trench must be excavated to the required depth. This must be hard when tested with a mattock. Concrete should never be put in loose soils. This can cause the house to collapse. The diameter for the reinforcement bars to use is from a quarter inch.
In a reinforced concrete foundation, the work commences by excavating a trench to required depths. The trench width is about two feet wide. The depth should be on hard ground and varies from site to site. High yield bars are cut and tied together. They are made into three long bars that will run the whole length of the trench. These will be the top bars. Additional bottom bars running the across the width of the trench are tied to the top ones. A spacing of eight inches is done when joining the reinforcement bars.
The foundation trench bottoms are made level to receive the concrete. A blinding layer of two inches thickness is then added to the trench and made level. The Thickness of the foundation concrete is marked with steel pegs driven into the blinding. This will mark the height of concrete which is eight inches thick. Reinforcement is then laid into the trench. This should not rest directly on the blinding layer. Spacer blocks are put underneath to allow the concrete to flow below. They provide cover to the steel. This spacers should be two inch thick.
Once the reinforcement is placed in the trench, concreting can proceed. care should be taken to avoid debris entering the trench. This should be cleaned out. In the case of a sloping site, the foundation is stepped a full masonry course. The concrete is mixed in the ratio of one part cement, two parts sand and three parts ballast. The ready mix is then poured into the reinforcements. It should be leveled with pegs already placed. It then spread as it is being vibrated. It should be thoroughly cured for minimum seven days to achieve strength.