There are different reasons why you should be interested in the different types of available concrete foundations. If you know the differences between types of foundations, it can save you money and time, both in the short term and in the long term, because there are many advantages and disadvantages to the each type of concrete foundation. Here is a summary of the practical differences between the various types of concrete foundations, which I copied from an interview with some St. Louis concrete contractors few months ago.
These are a very common type of concrete foundation. They are mostly seen in areas where the ground freezes as they are usually designed to resist damages from frozen ground. A flat section of footing is positioned deep under the ground and parallel to the surface in t-shaped foundations.
After which the foundation is then placed. The foundation is usually a taller and thinner slab that is parallel to the footing. T-shaped foundations get their name from the relationship between these two parts because the shape they create is similar to an upside down letter T.
T-shaped foundations have a layer of gravel immediately below the surface and above that, wire mesh is used to pour flat concrete. Then, this section is bolted to the t-shaped construction.
At the end, the result is a highly stable foundation that can survive anything thrown at it, among which is frozen ground.
Slab on Grade
Slab on grade foundations are also used widely but are generally only used in places that do not get cold enough to the extent of freezing the ground.
Like the T-shaped foundation, they also have a layer of gravel below them that provides drainage; but, even the single slab of concrete from which this kind of foundation derives its named is more complicated than it seems to be at first.
They are usually thicker at the edges than in the center and the thicker part of the foundation is connected to the thinner part by a gradual incline. Apart from this feature, slab-on-grade type foundations have different features that increase their strength and stability. For one, the slab contains a wire mesh for more durability. Also, the slab is reinforced by metal rods.
This type of foundations are used only in areas where the ground does not freeze. However, it is possible to insulate them so that they become resistant to frost and frozen ground. Because of this, slab on grade concrete foundations can sometimes be seen in areas with winters cold enough to result in the ground freezing.