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Slab Foundations: The Good and the Bad

A slab foundation is made from concrete that’s poured all at once on the ground. But is it the right type of foundation for you?

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If you are looking to build a home in an area with expansive soil like clay, your builder will likely recommend a slab-on-grade foundation as your home’s base. In this article, we explore this type of foundation and look at its pros and cons.

Slab foundation

What Is a Slab Foundation?

A slab foundation is a solid concrete slab that is usually four to six inches thick in the center and rests on the ground. The edges are generally thicker, about 24” wide, to allow for extra strength around the perimeter. A slab-on-grade foundation is suitable for areas with warm climates where the ground does not experience freezing and thawing as this can lead to cracks in the concrete and shifting of the foundation.

Slab foundations are placed on a layer of sand or crushed gravel to improve drainage conditions or to act as a cushion. But before laying the concrete slab, the property has to be graded. If not, the foundation could settle or sink due to poor soil compaction. Some contractors use post-tension beams or steel rods to reinforce the beams. These materials strengthen the concrete and increase its load-bearing capacity.

Houses built on slab foundations lack crawl spaces and have no space under the floor. If you are considering building a slab foundation, there are a few benefits and drawbacks that you need to take into consideration.

Benefits of Slab Foundations

Slab foundations have many advantages. Some of the most common include:

Cost Savings

Slab foundations are generally less expensive to build than other types of foundations. This is mainly because wooden members such as floor joists are not required, eliminating their cost. Also, since there is no crawl space under them, the utility costs associated with heating and cooling are lowered.

Relatively Easy to Build

The pouring of concrete slabs takes a single day, minus the prior preparations. Overall, the entire process can take four days to complete from start to finish, assuming the weather is not a problem.

Requires Less Maintenance

When built right, a slab foundation can last 80 to 100 years. A slab foundation is solid and thick, making it strong. Also, if built on areas where the soil does not freeze, homeowners with slabs have very little to worry about

Energy-Efficient

The lack of a crawl space in a home significantly lowers its utility bills associated with heating and air conditioning.

Less Risk of Mold, Mildew, or Insect Infestations

A concrete slab foundation can protect your home from mold and termites. This is largely due to the lack of space under the slab for mold to form or pests to nest.

Disadvantages of a Slab Foundation

Concrete slab foundation also has its share of downsides, like these:

Prone to Cracking

While concrete is naturally strong, it is prone to cracking due to weather, tree roots, soil settlement, and moisture changes. This can compromise your home’s structural integrity. Repairs could also prove challenging and difficult. 

Plumbing Inaccessibility

Another notable downside of a slab foundation is that plumbing pipes are all encased in the concrete. Even a small leak may require that you jackhammer the slab to fix it. This can create a huge mess that may also be expensive to fix. Also, it may be hard to detect a plumbing leak until you notice that your water bill is high.

Makes Homes Less Attractive

Some people find the lack of underground spaces and the lower-to-the-ground look of a slab foundation unattractive. This can negatively affect a home’s resale value.

Is your slab foundation experiencing settlement or slab fractures? Contact the professionals at Foundation Recovery Systems to schedule a free foundation repair inspection today.