Looking to start a building project? You might need some information as to what to be aware of like building plans, architecture, budget, and types of building foundations.

Not to worry, this article will shed some light on basic types of foundation you need to be aware of and which is most suitable for your structure and type of building you are planning to erect.

Foundations provide support for structures, transferring their loads to layers of soil or rock that have sufficient bearing capacity and suitable settlement characteristics. Basically, a foundation is like a framework where your building are constructed on. Constructing the right foundation is an integral part to your success as a builder or commercial real estate investors. A foundation is the integral structural element of a building, bridge and other similar engineering structures that primarily transfers the loads of the structure to the soil or strata underneath it. The foundation provides stability as they serve as the point of connection between the structure and the soil or strata bearing the load. There are different types of foundation depending on the type/ complexity of structure and the strata directly beneath it.

As a beginner in the real estate investment sector, its important to understand the different types of building foundations and which types fits a specific type of building or soil. Foundations can be categorised as shallow foundations or deep foundations. Shallow foundations are mostly used for bungalows or simple structures with low bearing capacity. Deep foundations are necessary where the bearing capacity of the surface soils is not strong enough to support the loads imposed by a structure and so they need to be transferred to deeper layers with higher bearing capacity. In some something areas of Nigeria with weak or swampy soil, deep foundations are necessary to maintain the strength of the building

The most common types of building foundations you might come across are:
Strip foundation
Raft or Mat foundation:
Pile foundation
pad foundation
Strip foundation
Strip foundations are most suitable for soil which are of fairly good bearing capacity. They are mostly used for light structural loadings such as those found in many low-rise or medium-rise domestic buildings – where mass concrete strip foundations can be used. In other situations, reinforced concrete may be required. In simple terms, strip foundations are used in light weight constructions like bungalows and is not advised to be used for story buildings and high rises. Older buildings may have brick strip foundations.

Strip foundation is commonly used:

For bungalow construction.
When the soil is fairly of good bearing capacity.
When light weight construction is to be done.
Very broadly, the size and position of strip foundations are typically related to the wall’s overall width. The depth of a traditional strip foundation is generally equal to or greater than the overall wall width, and the foundation width is generally three times the width of the supported wall. This results in the load being transmitted at 45º from the wall base to the soil. In Eastern part of Nigeria where the soils are hard and compact also accepts the use of strip foundation. strip foundation are generally cheap compared to raft and more popular in the eastern part of Nigeria as an acceptable type of building foundation for low rise buildings.

Soil recommended for strip foundations are:

Rocky soil
Uniform firm and stiff clay Soil recommended for Raft foundations are:
Soft clay
Peat
Raft foundation
A raft foundation, also called a mat foundation, is a continuous slab resting on the soil that extends over the entire footprint of the building, thereby supporting the building and transferring its weight to the ground

A raft foundation is a type of building foundation often used when the soil is weak or has a low bearing capacity, as it distributes the weight of the building over the entire area of the soil, and not over smaller zones (like individual footings) or at individual points (like pile foundations). This reduces the stress on the soil. consider a location like Ibeju Lekki part of Lagos or Ogun state, where the soils are relatively waterlogged. A raft foundation is need for any type of construction even in fencing. A raft foundation is more expensive when compared to a strip or pad foundation. A popular type of Raft foundations is Beam and Slab raft foundation. This foundation type can also be called mat foundation consists of a wide area of interconnected reinforced concrete ground floor and beams spreading over the entire footprint of the building. they are built on a soil with a low bearing capacity. Majority of buildings in the fast developing marshy areas of Lagos have a rafted foundation.

Raft foundation is commonly used when:

A building is to be erected on a marshy soil or water logged soil.
the soil can be sand filled.
Pile
A Pile foundation is usually a deep foundation with a slender column or long cylinder made of materials including concrete or steel, used to support structures transferring the load at the desired depth and could be by end bearing or skin friction. Pile foundation is mostly used when heavy loads from superstructure are imposed. A Pile foundation is usually a deep foundation with a slender column or long cylinder made of materials including reinforced concrete or steel, used to support structures transferring the load at a predetermined depth.

Pile foundation is commonly used when:

A bridge or building is to be constructed over a water body
heavy loads from superstructure are imposed.
When the groundwater table is high
heavy and un-uniformed loads from superstructure are imposed.
when soil excavation is not possible up to the desired depth due to poor spoil.
Soil recommended for Pile foundations are:

Soft clay
Foundations depending on the type can cost up to 20 to 40 percent of the building’s total construction cost. It is one of the most important component of a building, hence its construction must be managed and supervised by relevant and experienced construction professionals such as Builders and Civil Engineers.

Pad foundation
This type of building foundation is formed by a rectangular, square and sometimes circular spread of reinforced concrete footing. Loads from upper floors and roof are transferred to the beams while the beams transfer them to the columns and then to the pad footing and ultimately to the soil at a predetermined depth that has a suitable bearing capacity.

Pad foundation is used when:

Constructing a storey or high-rise building.
The bearing capacity of the soil beneath it is high
A popular type of Pad foundation is combined footing. Combined footings are constructed for two or more columns when they are close to each other and their foundations overlap.

Soil recommended for Pad foundations are:

Soft clay
Uniform firm and stiff clay
For more information on pad foundation visit click here

Conclusion

These are the basic and most common types of foundations we will be discussing, foundations types are not limited to these, they are still a few others that could be advised by your engineer depending on the nature of the building project. Now that you have a basic knowledge of foundations and soils they are suitable for, you will have a better understanding when discussing with engineers and professionals as to what’s to be done on your project. you can also contact us for your next building project as we have a team of construction experts that will bring your project to live. If you are new to the real estate world, before diving deep into investment and construction, you might want to check out our article on guide to real estate investment for beginners