A Guide To Pad Foundations
No matter what kind of structure you are building, foundations play an essential role in every project.
The main purpose of foundations is to provide structural support to a new building, ensuring they remain safe when they have been erected and, ultimately, will not collapse.
There is a wide range of different foundation types available to the construction industry, and shallow foundations are among the most popular.
A shallow foundation is a type that transfers structural loads to areas that are near to the top of the earth’s surface, rather than deeper into the ground where some foundations go.
Pad foundations are one of the most common shallow foundation types, and here at Concrete Supply UK we can provide our customers with a bespoke concrete mix to help build pad foundations to the highest quality.
In this article, we’ll take a closer look at pad foundations, explaining everything you need to know about them.
Read on to find out more…
What are pad foundations?
So, what is a pad foundation?
As mentioned above, pad foundations are a type of shallow foundation which means that they will always sit relatively close to the surface compared to other types.
However, unlike some shallow foundation types, pad foundations can be installed deeper in the ground as well as the soil conditions allow for it. These foundations will take the form of square, circular or rectangular concrete pads that spread the load of the structure across the layer of soil or rock that is below it. The foundations will be located directly below point loads in the structure above such as columns or ground beams.
The shape of the foundation will be chosen based on what is the most efficient for the specifics of the individual project. For instance, circular columns will sit above circular foundations.
Pad foundations are also normally flat or a consistent thickness but sometimes they may also be stepped if it is beneficial to the project. This will depend on the nature of the load above and the bearing capacity of the ground below.
The pads will also be arranged depending on the nature of the project, with the most common arrangements including:
- A series of separated pads
- Balanced pads that support more than one point load
- Continuous pads that are close together
- A pad and beam arrangement where a series pads support a continuous beam
These foundations are typically used for larger structures that have been purpose-built, including industrial environments or commercial buildings where large roofs will need to be supported.
Types of pad foundations
There are various sub categories of pad foundations including the following:
Plain concrete pad foundations
Pad foundations that use plain concrete do not require any reinforcements meaning they should only be used for lighter loads or smaller structures. These are often known as footings and they sit at the base of a column or other point loads.
Reinforced pad foundations
Sometimes, pad foundations may need to be reinforced. While this is not exclusive to pad foundations, in these instances a metal cage that has been built to be the correct size for the project will be installed. It will also feature a steel rebar, or reinforcing bar, which is a device that is used to add tension to the foundation. This may be needed if durability has to be enhanced as it will prevent cracking from occurring. Cracking can be hugely damaging to foundations and will actually compromise the safety and integrity of the whole structure, so these reinforcements are extremely important.
Combined column pad foundations
If two columns are being installed relatively close to one another, then combined column pad foundations may be required. This type of pad foundation can help support the load of the two columns, and they are usually rectangular and symmetrical in order to ensure the columns are as balanced as possible when they have been installed.
Continuous pad foundations
If lots of columns or beams are being placed relatively close together, they will likely need to be placed on continuous pad foundations. This helps to reinforce the columns, and this reinforcement will pass through the entire length of the foundation to add an additional layer of stiffness and robustness to reduce the impact of differential settlement. Differential settlement is the term for when one part of the ground supporting a foundation moves quicker than another area – the Leaning Tower of Pisa is perhaps the most famous example of this.
As well as the various types of pad foundations discussed above, they can also be used in conjunction with ground beams which help to boost stability of the foundations.
Benefits of pad foundations
There are several great benefits of using pad foundations in the construction process. Let’s take a look at some of the key advantages:
Minimal excavation required: As they are a shallow foundation, pad foundations typically require very little excavation compared with other foundation types. This means project timelines can be sped up and less labour is required.
Cost-effective: Pad foundations use less concrete compared to other foundation types like raft or strip foundations, which makes them more economical. As mentioned above, they also require less excavation which leads to lower labour and machinery costs.
Simplicity in design and construction: The construction process for pad foundation is extremely straightforward, which can lead to a faster project completion. The simple design also reduces the need for specialised skills or over-complicated construction techniques.
Versatility: Pad foundations are suitable for various types of buildings and structures, particularly where loads are relatively light and soil conditions are favourable. They can also be used on different soil types provided the soil has adequate bearing capacity.
Stability and load distribution: Pad foundations are also great at distributing structural loads directly to the underlying soil, minimising differential settlement. They are also ideal for supporting individual columns or beams providing localised stability and support.
At Concrete Supply UK, we can provide you with bespoke mixes and different types of concrete to help you get your next project done to the highest quality. For more information, contact our expert team today.
