A good foundation is the start of any well-crafted structure. The type of foundation used is based on the type and size of the building, as well as the safe bearing capacity of the surrounding soil.
Before beginning any construction project, you should first have a general understanding of the types of building foundations available. There are also benefits and common uses for each, which might help the decision process.
Let’s take a look at the different types of foundations there are and uses for each.
Shallow and Deep Building Foundations
Building foundations can broadly be placed into 2 categories – shallow and deep. This refers to the depth of the soil in which the foundation will be placed. Within each of these 2 categories lies various types of foundations, or footings, that can be used.
When discussing shallow foundations it means that the depth in which the footing is placed is less than the width of the foundation. Another term for these foundations is a spread or open footing. The concept is that the load of each column is spread out over a larger area.
A shallow foundation’s design varies also. Some options that we’ll discuss include wall footings, strip footings, and mat foundations.
These types of footings run the entire length of the wall and help distribute the weight of the load evenly into the ground. Wall footings provide better stability by dispersing the weight over a larger area.
Wall footings are generally used for individual columns and may be constructed from brick, cement, and concrete.
Strip footings are essential they’re – a long strip that helps support the weight of the entire wall. You often see strip footings in older building constructions that use masonry.
Strip footings do not use individual columns, such as wall footings. If there are columns, they are generally so close together that the spread footings touch or overlap.
Mat foundations are used for heavy structural loads. This is because the weight of these structures is spread across the entire area of the building. Mat foundations are often used when a basement is being built. Here, the entire slab of the basement acts as the building’s foundation.
Deep foundations have a depth that is greater than the width. Here, the load of the structure is dispersed vertically instead of horizontally. Some of the most common deep foundations are pile and pier.
A pile is a long, circular piece of concrete or other material that is pushed into the ground and then used to support a structure.
Pile foundations are used for high-rise structures with heavy, concentrated loads. They are also used when the top layer of soil is not strong enough to support the building’s weight and the foundation must rely on a deeper, stronger layer of soil.
There are also different types of pile foundations including friction and bearing.
Pier foundations are similar to pile but don’t go as deep into the ground and can only transfer a load using bearings. This type of foundation is often made from wooden posts or concrete piers and can be more cost effective than concrete foundations.
As you can see, the type of structure, weight of the load and condition of the surrounding soil all play a part in the type of building foundation needed.