Homes in the U.S. mostly have either a basement, crawl space, or concrete slab foundations. While basements are most common in the northern part of the country and crawl spaces are preferred in less humid areas, slab foundations are usually used in the Southern U.S.
While homes with slab foundations don’t have that extra storage space, homeowners still choose them because they don’t require a lot of excavation, can be quickly constructed, and are cheaper to make than a basement or crawl space. Apart from being used as building foundations, slabs are also used in floor construction. Thinner paving slabs are used as exterior paving materials and are ideal for patios.
Let’s explore the pros and cons of slab foundations and take a look at how they are built.
What Is a Slab Foundation?
A slab foundation is made of concrete and it is reinforced with steel rods. This type of foundation is built over soil-based areas and is usually four to eight inches thick. However, its edges are usually thicker than the rest of the slab to add strength to the perimeter. A slab is not poured in layers, but all at one time.
After the concrete has cured, the structure can be constructed on top of it. This type of foundation is mostly used in parts of the county with warmer climates, such as Florida.
How to Build a Slab Foundation
If your builder is constructing a slab foundation for you, they will need to take the following steps:
- Depending on the size of the home and soil conditions, the contractor will determine the width of the foundation. In an ideal case, it should have the same dimensions as the structure that will sit on top of it.
- Builders will remove the sticks, rocks, and roots from the ground to prepare the property for construction.
- Afterward, the slab area should be framed with pre-made 2×12-inch boards.
- Builders will dig footings along the inside of the form, about three feet from the edge.
- Next, the soil will be compacted with a tamper.
- Builders will put rebar stakes into the trenches and tie them together. These stakes need to cover the whole area.
- When rebar stakes are in place, contractors will mix sand with mortar, pour it into the footers, and leave it to dry.
To reinforce the slab, builders will use post-tension cables and steel rods. This way, the foundation will be sturdy enough to bear the structure’s weight. The slab is placed in a layer of sand to improve drainage conditions and prevent water from accumulating next to the foundation. Since settling is a big problem that can compromise the structural integrity of the building, a slab foundation needs to be constructed on grade soil so it won’t shrink or settle.
Benefits of a Slab Foundation
There are many reasons why homeowners opt for this type of foundation.
Economical: Since it doesn’t require so much construction material and it can be quickly built, the slab foundation is cheaper than other types of foundations. In addition, it requires very little maintenance to stay in a good shape.
Easy to construct: As mentioned, a slab foundation can be quickly constructed. This is because there is little excavation involved and builders use poured concrete that cures in a matter of days. Since contractors won’t stop the construction work to wait for the foundation to cure, there are no delays in the process, and homes are built much faster.
Reduced mold growth and pest Infestations: For a lot of homeowners, mold growth and pest infestations are their worst nightmares. While pests can damage the support beams, feed on construction materials, and even leave feces all over the place, airborne mold spores can contaminate the air in the entire home and cause health problems. Luckily, with a slab foundation, there is no need to worry about such problems. Because concrete slab homes don’t have openings or empty space underneath, they are not prone to this type of problem.
Easy to extend: If you wish to add another room, you can easily extend your slab foundation, and for a small price. Of course, this is not something you should do on your own, so call your contractor and elaborate on your plans.
Durable: If high-quality materials are used and no mistakes are made during the construction, a slab foundation can last more than 100 years.
Easy to decorate: If you wish to make the foundation more aesthetically appealing, you can easily stain it or texture it.
Cons of Slab Foundations
Of course, just like any other type of foundation, concrete slabs also have their downsides:
Cracks: Unfortunately, since they are made of concrete, slab foundations can crack with time. A lot of factors can cause cracking, such as soil displacement, frozen ground, earthquakes, and tree roots. These cracks can compromise the structural integrity of your home.
Less protection: This type of foundation does not offer sufficient protection to homes during storms.
Lack of storage space: While homeowners who have basements and crawl spaces can use them to store things, homes with slab foundations do not have below-grade space.
In summary, slab foundations are a great choice for future homeowners who do not wish to spend a fortune on their new home and are not concerned with storage space. However, for the concrete slab to stay in a good shape, it needs to be moisture-free.
If you wish to invest in waterproofing measures and protect your slab foundation against moisture, contact experts at AFS. Whether you live in Tennessee, Alabama, Mississippi, or Georgia just schedule a free estimate and one of our inspectors will come to your home and provide recommendations after a thorough inspection.