When you start your construction process, you may undergo several procedures and steps to ensure the structural stability of a building. Because the foundation is crucial when it comes to building construction, the foundation is referred to as the base, whereas the footing is its main component. Footing has its unique significance and characteristics when it comes to building a structure, ensuring its durability and longevity.
In this Brick and Bolt blog, let us explore more details about the types of footings, applications, building processes, advantages, and disadvantages of footings.
What is a Footing?
Footing is an essential component of building construction, as it gives a building’s base structural stability and transfers the load from the structure to the ground. Each structure deserves a unique footing based on the location, soil conditions, and other environmental factors. Therefore, the stability of a structure can be greatly impacted by the types of footings utilised in building construction. To satisfy the requirements of various building projects, footings are often composed of concrete or masonry and come in a wide range of sizes and shapes.
Types of Footings
For effective transfer of loads from the structure to the ground, different footings are built for different construction projects. They are usually constructed depending on the building’s size, soil conditions, and load capacity. Here is a brief overview of the most typical footing types:
This footing is long and narrow, and it extends the entire length of a wall. Usually shallow, it is effective for smaller load-bearing walls.
Spread Footing
Spread footing offers a reliable foundation for individual posts or columns. As they are stronger and wider than strip footings, they are perfect for supporting larger walls or columns to prevent settlement. They are built in various shapes such as round, square, and rectangular.
Combined Footing
A combined footing is used when two or more columns are too near to one another for separate footings. A common broader foundation can be built to support multiple columns.
Isolated Footing
This foundation, which is often round or rectangular, supports a single column. Isolated footings are usually larger and deeper, made to support the weight of a single column.
Mat or Raft Footing
A mat footing is a sizable slab of concrete that covers the entire foundation area of the building. It is frequently utilised for large structures and disperses the load equally across the ground.
Pile Footing
Pile footings are used when the earth isn’t sturdy enough to hold up a structure. These are lengthy, deeply buried steel or concrete columns that offer additional support.
To ensure the foundation is secure and dependable, each type of footing is selected according to the building’s design, the state of the soil, and the structural requirements.
Application of Footing
Residential Buildings:
Through supporting slabs, walls, and columns, footings give dwellings stability.
Commercial Structures:
Used to distribute large loads and provide durability in offices, warehouses, and shopping centres.
Industrial plants:
Footings are made to endure vibrations and support large machinery.
Bridges and flyovers:
Footings are crucial for maintaining the stability of bridge piers and abutments during extreme weather conditions and loads.
High-Rise Structures:
To withstand seismic and wind activity, deep foundations secure skyscrapers to stable soil layers.
Footings keep walls stable so that soil pressure doesn’t cause them to collapse.
Water Tanks and Silos:
Footings can distribute weight uniformly to ensure a safe installation.
They offer a sturdy foundation for durable walls and fences.
Sloped Terrains:
In hilly regions, stepped footings provide level platforms.
Infrastructure Projects:
Footing ensures the safe operation of roads, tunnels, and dams.
The Building Process of Footing
One of the first things that is done immediately after excavation is the construction of footings. The first step in the process is digging a hole for the footing. The size of the building and the type of soil determine how deep this hole should be. It must be deep enough to remain beneath the freeze line (where the ground freezes) and above any soft or loose soil.
When the hole is prepared, the footing is built by either pouring concrete into it or by utilising brick blocks, stone, or pre-made concrete. In order to adequately sustain the weight of the building, the footing needs to be level and extend past the hole’s sides. The foundation walls are built on top of the completed footing.
Advantages of Footing
- Footings ensure stability by distributing a building’s weight uniformly across the ground, avoiding excessive stress on any one area.
- They can spread the weight on softer soils or reach deeper levels for strength, depending on the type of soil.
- Footings keep constructions from tilting, sinking, or breaking by preventing uneven settlement.
- Additionally, they stabilise buildings in the face of extreme weather by anchoring them against natural forces like wind, earthquakes, and floods.
- By raising the foundation above ground dampness, footings protect the building from mould and water damage.
- To guarantee correct alignment, they offer a sturdy, level foundation for walls, columns, and other components.
- Footings are modified to provide sturdy platforms on sloping terrains, enabling safe building even on uneven terrain.
Disadvantages of Footing
- Building a footing can be costly due to the substantial labour and material requirements.
- The entire construction schedule may be extended by the footing design and construction process.
- Unsatisfactory soil conditions may necessitate reinforced or deeper footings, which would raise the cost and complexity.
- Unfavourable weather conditions, including persistent rain or extremely cold temperatures, might make installing footings take longer than expected.
- Footings may need constant upkeep, particularly in locations with shaky soil or subpar design.
What is the Difference Between a Footing & a Foundation?
| S.No | Aspect | Footing | Foundation |
| 1 | Definition | The part of a building’s foundation that directly supports and distributes the weight. | The complete structural system that supports the building, including footings and foundation walls. |
| 2 | Purpose | Provides stability by distributing the load of the building. | Supports the entire structure, ensuring its stability. |
| 3 | Location | Located beneath the foundation, in direct contact with the soil. | Extends from the footings to the surface, including walls, slabs, etc. |
| 4 | Role in Settlement | Helps prevent differential settlement by spreading the load evenly across the soil. | Ensures the building is securely anchored to the ground. |
| 5 | Construction Requirement | Typically required by building codes to ensure stability. | Essential for supporting the entire structure, may or may not include footings. |
| 6 | Material | Usually made of concrete, stone, or brick. | Can be made of concrete, stone, brick, wood, or other materials depending on the type. |
| 7 | Risk of Failure | Improper footings can lead to foundation instability and cracks. | Weak foundations may lead to structural collapse or significant damage. |
| 8 | Maintenance | Regular inspection is needed to check for cracks or water accumulation. | Requires periodic checks for settlement, water damage, and structural integrity. |
Factors to Consider in Footing Construction
The factors that need to be considered are as follows:
Soil Type: The size and depth of the footings depend on the kind of soil. While weaker soils could require larger or deeper footings to maintain stability, stronger soils can support greater weight.
Climate: To avoid settling or damage, footings may need to be deeper in places with a lot of rain or extremely cold weather.
Building Weight and Size: While smaller buildings could require less sturdy footings, larger and heavier structures require more.
Type of Building: Lighter constructions, such as residences, can employ shallow footings, but taller buildings need deeper, stronger ones.
Lateral Forces: To maintain the stability of the building, footings must be made to withstand forces such as wind and earthquakes.
Building Codes: To ensure safety and compliance, local building codes establish minimum requirements for footing design, including size, depth, and materials.
Conclusion
Footings are often overlooked, but they are vital for a building’s stability. They help transfer the weight of the building to the soil that can support it, ensuring the structure lasts.
Whether to employ piles, individual, combined, raft, or strip footings will depend on the style of structure and the condition of the land. The water table in the area, soil strength, frost line depth, and local building codes must all be taken into account while designing footings.