When many of us think about the foundations of a building, we picture walls that are built and buried beneath the surface of the earth to give a firm hold so the building attached above doesn’t move – and rightly so, as that is basically what foundations are and what they’re used for. But it’s not as simple as just digging down to a certain depth and starting to build your foundations on the bare earth because even foundations need a solid surface to be built on, otherwise they may shift and sink. This is where concrete footings come in, a very important part of constructing houses and many larger buildings. The type of footing and method of installing said footing varies greatly from job to job but the basics remain the same. Usually a trench is dug to a size that matches to specific calculations of the job. Depending how high, wide or heavy the building is going to be will depend how big the trench used for the concrete footings will be. The trench will then be filled with cement, levelled and once hardened, construction of the foundations can begin. The flat surface of concrete footings will distribute any weight placed upon it evenly, to minimise any chance of movement or sinking into the ground below.
Concrete footings are also used in the construction of smaller structures like brick garden walls. A trench is dug, usually 1 foot deep by 1 foot wide, with length depending on the individual project. The trench is then half filled with cement, which is then levelled and allowed to go off. Once hard, the bricks can then start to be laid on top of this new footing. This will not only stop the wall from sinking (as long as the footing doesn’t) but will also keep the wall perfectly straight and level. Once the wall has been completed, the cavity around the bottom of the brickwork can be filled with soil, sand or hardcore. There is no need to use cement unless you want to secure it further.
Obviously, concrete footings are not suitable for every situation. Skyscrapers for example will require impressively deep foundations, which are usually concrete and/or steel piles that are driven deep into the ground to give the most secure hold possible. Concrete footings are also not used in very moist environments where the ground is saturated with water, riverside or beachside homes for example where piles are also then used.