19 June 2024

How to calculate the thickness of your concrete slab

To pour a concrete slab for a terrace, a driveway, garage or a pool deck, you need to be aware of the precise concrete mix needed. Fortunately, through a simple calculation, you can determine the volume of concrete required for your task! Here is what you need to know to successfully complete your construction project.

Determining the thickness of a concrete slab is an essential prerequisite to order the right quantity of ready-mix concrete for your project. This is no simple matter: the thickness, determined by the engineer, influences the quality and lifespan of your structure. Thus, to avoid any cracks over time and to ensure adequate resistance of your construction, the quality of concrete and reinforcements alone are not enough as prerequisites! Please note: unlike a slab that is considered light, additional thickness of your concrete will not only increase the weight of your structure but also the construction cost. Finding the right balance is thus crucial!

Precautionary measures to undertake before preparing the concrete slab

Several factors need to be considered before embarking on a calculation, as the thickness of a concrete slab depends on several parameters. First, we need to consider the nature of the structure itself: depending on the intended use of the project, the slab may need to be thicker or thinner. For instance, the structure will be different if it is being used as a parking lot for multiple vehicles or as a pedestrian walkway.

The nature of the soil where the slab is being poured is another important element to consider: if it is loosely-packed or heterogeneous, it will require further reinforcements with a layer of compact gravel of at least fifteen centimetres.

Lastly, the materials used also matter: not all ready-mix concrete mixtures have the same level of strength and reinforcements tend to affect the rigidity of the structure. Be sure to follow the best recommendations for optimal performance!

To calculate the theoretical volume of concrete needed for your slab, the following formula is generally recommended: volume (m3) = slab area (m2) * slab thickness (m) = length (m) x width (m) x height (m).

Slab thickness according to the type of project

Depending on the project planned and on the level of the pressure applied on the slab, its thickness will need to be adjusted. Here are the common standards for various scenarios:

Concrete slab for a terrace:

Approximately 8 to 10 cm thick, this slab can handle light pressure and cannot support heavy loads.

Concrete slab for floors:

Typically around 15 cm thick, but it can vary based on factors such as the floor’s location and size.

Suspended concrete slab for a garage:

Generally between 15 and 20 cm thick, but this can vary depending on the garage’s intended use, such as storing multiple vehicles or whether it includes a shelter.

Concrete slab for a garden path:

The thickness usually depends on whether it’s a pedestrian path (8 cm is usually sufficient) or a driveway (then we recommend using 10 cm).

Feel free to reach out to our team for personalised advice. We can guide you on choosing the right thickness of your concrete slab based on the recommendations of the engineer, and will be glad to walk you through the amount of concrete needed, as well as our product range, to make your project all that more stylish!

Vous êtes convaincu ? Alors contactez notre équipe pour découvrir nos solutions sur mesure et notre accompagnement sur votre chantier, ou découvrez notre calculateur de matériaux pour évaluer vos besoins en béton.

  • Partager: