Under every home, there is a foundation that supports the structure; beneath most foundations, there are concrete footings. These elements are designed to support the foundation and prevent settlement. They need to be constructed by the book or your home won’t be structurally stable.
To ensure that the concrete footing will provide needed support, contractors need to assess the soil it will be poured on. They will then determine their size and exact location. When these calculations are not done correctly, the foundation will have many problems that are not that easily fixed. Let’s take a closer look at what footings are as well as their characteristics.
What Is a Concrete Footing?
The size of the footing depends on the size of the structure. Naturally, the bigger the structure, the bigger the footing. This element is made from concrete that is poured into an excavated trench and reinforced with rebar. Another factor that must be taken into consideration during the construction process is the bearing capacity of the soil. Unstable soils can cause problems such as settlement and lead to structural damage. In addition, moisture content also plays an important role. When all the factors have been taken into consideration and the footings have been built properly, they can support the foundation and the entire structure.
Building a Concrete Footing
Constructing a concrete footing entails several steps. First, the builders need to excavate the soil to make room for the footing and set up the formwork. Then, they need to mix the concrete while making sure that other unwanted ingredients don’t end up in the mixture.
Once the concrete is mixed, it should be poured into the trench within the next 30 minutes, or it will begin to set outside of the forms. Afterward, the contractors will bring the refill material or soil, and compact it at the base of your home. Moving on with the construction is only possible when the concrete has completely cured.
Factors to Consider When Building a Footing
To make sure that the concrete footing will support the foundation, two factors need to be taken into consideration before the construction begins. Soil condition and moisture content can significantly impact the footing and make it far less reliable.
Different types of soil behave differently when exposed to the weight of a structure. This is why soil conditions need to be analyzed before the concrete is poured. The footing can sit on one of three types of soil. Man-moved soil is any soil that has been dug out at one location and then moved to another location. Backfill soil has been excavated so that the footings could be constructed and then placed back to fill the gaps between the concrete and earth. The third type is native soil, which has not been disturbed in any way.
Each of these soil types responds differently to moisture and temperature. Before the footing is constructed, an engineer needs to inspect the soil and determine whether it will be able to bear the weight of the structure. Even if the soil is unsuitable, it can be removed and replaced. Another option is to mix the existing soil with aggregates to boost its load-bearing capacity.
It is important not to pour the concrete into completely dry soil. If that happens the soil will suck the water out from the concrete mixture and the concrete will end up being a lot weaker than predicted. Because of this, it is important to dampen the dry soil before construction begins. However, since different soils react to moisture differently, they should be moistened differently. For example, clay soil should be dampened with a small amount of water since it is not absorbent. It is not good if the soil is too damp either. Excess water in the ground can disturb the water-to-cement ratio and weaken the footing. This is why experts need to check the moisture content of the soil before construction takes place.
The Purpose of a Concrete Footing
The main purpose of a concrete footing is to support the foundation and ensure the structural stability of the home. Since footings help prevent foundation settling, they need to be correctly built and there is no room for mistakes. Because constructing a foundation on bare earth can lead to foundation cracks, the concrete footing is there to prevent such problems from occurring. It will protect the foundation from environmental loads and damaging natural forces.
Not all structures have footings beneath the foundation. Lighter ones are not that prone to structural damage and do not need a footing.
If the contractors make a mistake and the footing is not able to support the foundation, sooner or later settling can occur. If your home is settling, you will notice signs such as cracks in your foundation walls, tilting chimneys, and cracks around the doors and windows. One other sign that something is wrong with your foundation are sticking doors and windows.
If you are worried that something is wrong with your foundation or you just want to take a preventative approach, contact professionals at AFS. We serve areas in Alabama, Georgia, Mississippi, and Tennessee. Contact us today to schedule a free inspection. One of our experts will inspect your foundation, notify you if there are any problems, and suggest the best repair solutions.