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The foundation of any building is the piece of the structure that connects the rest of the building to the ground. Everyone knows what a foundation is, but not many people know how it’s made, or what types of foundations there are.

If you’re investing in commercial real estate or endeavoring into a commercial construction project, this is something you’ll want only the best information on—this can empower you to make informed decisions about your property or project.

 

What Exactly is a Building Foundation?

In engineering, a foundation is the part of a structure that connects a building to the ground. The foundation also transfers the building’s weight load from the structure to the ground. There are shallow and deep foundations, depending on the nature of the structure.

 

The Purpose of a Foundation

To transfer the weight load evenly to the soil

The foundation distributes the building’s weight load evenly across the earth, so no part of the soil is over-burdened. This is important for obvious reasons, and the most famous example of a foundation failing to do this is the Leaning Tower of Pisa, in Italy.

 

To anchor the structure

Usually, a foundation anchors the structure against natural forces. These forces include strong winds, storms, tornadoes, hurricanes, earthquakes, and more. In Japan and other countries with major seismic activity, many skyscrapers have special foundations that allow the buildings to “wobble” during an earthquake and prevent them from collapsing.

The anchor also prevents the building from being overloaded. The foundation receives force from the building and evenly distributes it on its way to the earth. This stabilizes the whole structure and prevents collapse.

 

Provide a level surface for construction

Buildings usually need to be built on a solid plane—and the foundation provides exactly that.

 

Prevent movement in the structure

In some cases, like places prone to earthquakes, the foundation partially exists to prevent lateral structure movement. Foundations always exist to prevent vertical structure movement, so the structure neither collapses nor sinks into the earth.

 

How is a Foundation Built?

Historically, foundations have been built from a number of materials:

  • Earth-fast foundations, otherwise known as post-in-ground foundations are made by timber pilings inserted into the earth. 
  • Padstones are stones on which many buildings rest. These simple foundations spread the weight from the wooden building to the earth evenly.
  • Stone foundations are made by dry stones, and stones laid in mortar. These common foundations provide flat working spaces on which to build. They also make for solid, lasting bases for structures.

 

Modern Commercial Construction

In modern commercial construction, there are three main types of foundations. Each one serves a different purpose and benefits from different scenarios. 

Almost all foundations nowadays use reinforced concrete, no matter what type of foundation they are. This goes for commercial as well as residential constructions.

Modern foundations make extensive use of footings. Footings are made from concrete, reinforced with rebar. They are poured into dug-out trenches. Their purpose is to support the foundation and prevent “settling.” Settling is the tendency for a structure to sink into the ground over time.

Finally, all foundations must be constructed with some excavation first. The process basically involves removal of all debris, such as tree stumps or stone, plus existing structures. During excavation, any holes made in the earth from things like tree roots are compacted with soil. Once the whole area has been cleared and compacted, the construction of the foundation is ready to begin. Read more about site clearance for a foundation here.

 

1. T-Shaped Concrete Foundation

This is the most commonly used commercial building foundation. It’s good for supporting tall buildings in seasonal climates that have freeze and thaw cycles. Frozen ground puts high pressure on the foundation. The T-shaped foundation is unique in that it resists much of the damage from frozen grounds. 

Normally, a flat footing is placed just below the normal frost line, with (foundation)walls built on top. The building’s walls are built slightly wider than the footings. The slightly wider walls provide an extra level of support to the building. 

T-shaped foundations have good overall stability and resistance to problematic soils.

How it’s made:

  1. Footing is placed.
  2. Walls are constructed and poured.
  3. Slab is placed by pouring between the walls.

 

2. Protected Shallow Foundation

Also known as frost-protected-shallow foundation (FPSF), this foundation type is usually used in colder climates. FPSF uses insulation on the outside of the foundation. The FPSF is usually 12-16 inches below the surface of the earth, so it saves quite a lot of money in excavation costs. The low grade (build depth) makes it a great economical way to build, as well as a fantastic way to avoid damage from frost heaves. Frost Protected shallow foundations only work on buildings with internal heating systems. 

How it’s made:

  1. Insulation is laid.
  2. The wall is poured inside where the insulation was laid.
  3. Another layer of insulation is placed at the base of the foundation wall.

 

3. Slab-On-Grade Foundation

This foundation type is used in places that don’t have freezing weather. Therefore, there is no need to build a frost-resistant shallow foundation or a T-shaped concrete foundation. 

Slab-on-grade is made with concrete poured to form a slab. The slab is made to be flat and several inches thick. It provides stability and a level place on which to build.

How it’s made:

  1. The slab is poured all at once. Once the foundation is excavated and the slab is poured, it’s done.

 

Getting a Good Foundation

There is a lot that goes into getting the right foundation for your commercial construction project. It will depend on what the building type will be, how it will be used, and the environment it will be erected in.

If you are unsure where to begin, then look to Reliable Commercial. Reliable Commercial is the best commercial construction company in the Dallas/Fort Worth Area. We have over 35 years of experience serving in Texas, Louisiana, and Oklahoma.

Even if you aren’t ready to build, contact us and talk to a commercial construction contractor about what kind of work you want done. A good building needs a solid foundation, it’s as simple as that!