Does A Concrete Slab Need Footings? (Answered)
Some years back, most houses were built without footers underneath the concrete. Instead, the contractors only dug shallow trenches in the dirt then built the walls on them, which saw many homes be without a full basement.
Footings are an essential part of any construction exercise. The footings will give the foundation of your building enough support and protect it from shifting and heaving because of thaw cycles. It also protects water runoff from destroying the slab and having it in good shape without cracks and splits. So, it’s safe to say that the concrete slabs need footings.
To make footings on a concrete slab, you start by including footings into your building’s foundation by making a 12-18-inch-deep trench towards the foundation’s edge. Then, reinforce it with rebar, pour concrete and slab simultaneously on this trench to get a strong foundation. To understand more, this article offers a complete guide.
What Are Footings on A Concrete Slab?
Footings are an essential part of the foundation of your house. They consist of concrete and rebar reinforcement that is poured into a drenched trench. The footing’s main work is to offer firm support to the building’s foundation and protect it from settlings. You should have footings in concrete slabs, especially in areas that have problems with their soils.
Why a Concrete Slab Need Footings?
So does a concrete slab need footings? Unfortunately, yes. A concrete slab needs footings for various reasons:
A concrete slab with footings will help you have your building serve you for longer because it makes its foundation strong. Without the footings, the slab will not be in perfect shape, and anything you build over it will be damaged within no time.
Even if you’re in a colder region, a concrete slab with footings will not experience regular heaving, tilting, and cracks. Water runoffs will also not destroy a shallow slab with footings which prevents you incur additional costs of putting it into shape.
Apart from that, you need to have footings for your concrete slab to comply with the building codes. Also, you’ll be able to keep animals from burrowing under your building’s foundation. So, it’s important to have footings for your concrete slab, whether you’re building a garage, home, or any building you want to have served you for long because of a strong foundation.
In most states, it’s a must to have a concrete slab with footings to be issued with a building permit. Additionally, you’ve got to prove that you carried out the plans and made a foundation with the right footings.
How To Make a Concrete Slab with Footings?
As you keep up with the building codes, you also need to understand how to make concrete slab footings. However, you need to note that this will differ from place to place because every area has its building codes.
You can incorporate footings into your concrete slab by:
- First, you need to decide on the area you want to have the building in. Then excavate it by digging deep so that 3 inches of gravel and 4 inches of concrete go in.
- After that, label an area of 18 inches wide along your slab’s perimeter.
- Then dig an 18-inch wide and 21-inch-deep trench to enable you to have a thicker foundation than the slab.
- Put a vapor barrier (heavy duty plastic) on top of the dirt in the trench or slab.
- Then pour 3 inches of gravel on the concrete slab area. Finally, put another 3 inches of gravel on the edges of the perimeter trench.
- After that, put rebar on the trench properly to avoid resting on the bottom of the trench.
- Also, put the rebar on the slab area.
- Then pour the concrete on the slab and concrete area until they fill up.
- Finally, smoothen and finish your concrete foundation.
Ensure you do all this to enable your concrete slab to be strong and durable regardless of your location.
Do All Concrete Slabs Need Footings?
Although some people ignore putting footings on the concrete slabs, it’s advisable to do so. You should do this regardless of the building codes since it’s for your benefit. Also, remember a building with footings on the slab will stand the test of time, and you’ll not spend much money doing repairs around the house.
A building without footings will give you more challenges and lose its value faster. But ensure you put thick footing to support the weight of your building walls.
What Will Happen to A Building with A Concrete Slab but No Footings?
If you’ve got a concrete slab without footings, know that your building is a disaster waiting. This is because the concrete slab will crack, leading to some destruction to your building. The worst part about this is that the slab concrete will tilt and shift, resulting in the building on top of it becoming weak as time goes by.
You’ll also have problems with burrowing animals since it’s the footers that repel them. These animals will also bring you trouble in your house as they’ll damage other valuables within the property.
What Type of Concrete Slab Can I Make Footings on?
There are three types of concrete slabs, and each requires footings to remain strong.
T-shaped concrete slab
First, you can make footings on a t-shaped concrete slab. This type of concrete slab footing best suits areas where the ground freezes. So, you need to put footings under the frost line before adding the walls on top.
Slab on Grade Foundation
The other concrete slab which you need to install footings is the slab on grade foundation. It should be thicker at the edges to enable you to get integral footings. Adding wire mesh will enable your slab concrete’s footing not to have cracks. This is an ideal concrete slab for non-freezing areas.
Another slab you shouldn’t forget to add footings to is the frost-protected foundation. Footings in this instance will help in the heat regulation preventing the surfaces around it from freezing.
Can You Pour Concrete Directly on Dirt?
It’s not advisable to pour concrete on a dirty surface to prevent the slab from cracking or shifting. If you do, you’re likely to have tilted sidewalks and weak slabs. In addition, a concrete slab made on a dirty surface is likely to harbor moisture which will destroy it.
Pour three-inch gravel over the soil before adding the concrete. The gravel will also make your concrete slab durable.
What Kind of Footing should I Use for My Concrete Slab?
The kind of footing for your concrete slab depends on the type of building you want to have. The footings reinforcement, width, and depth will vary depending on the local area building code. However, you need to ensure you follow the right procedure when making the footing to enable the concrete slab to serve you for long.
So, does a concrete slab need footings? Yes. The footings will enable you to have a strong building as it gives the foundation support preventing the walls from cracks and shifting. It will also keep away burrowing animals who burrow below the foundation, making it weak.
However, you need to follow the right procedure by digging the right size footings and then reinforcing them with rebar. Note that you shouldn’t pour concrete on contaminated soil, which will interfere with the quality of your slab.