Understanding Load Bearing Capacities for Commercial Concrete Flooring

Concrete flooring is a good choice for commercial and industrial properties because of its durability and resilience. With natural strength, even a standard concrete with minimal thickness has impressive load bearing capabilities. 3000 psi is the standard of compressive strength on a concrete slab.

But this is only a base capability of concrete. With adjustments to the initial concrete mixture and the installation process, and by utilizing an experienced commercial flooring contractor, it is possible to increase the concrete weight limit significantly so that it can stand up to more demanding commercial applications, such as the weight of heavy machinery or industrial equipment.

At Colorado Concrete Repair, determining the concrete weight limit and how to achieve them with a concrete installation is part of our reverse engineering process. There are many customization options available with concrete and other commercial flooring. By first determining the specifications that your floor needs to meet for both your industry and the way you regularly use it, our team can use our knowledge of concrete flooring installation to plan and install a floor that will meet those specifications.

Factors Impacting the Compressive Strength of a Concrete Floor

Compressive strength is the strength with which something can push on a concrete surface without causing it to bend, crack, or otherwise break. The compressive strength directly corresponds to its load bearing capacity. To increase the concrete weight limit, there are several different factors that we may adjust to reach the necessary compressive strength. These include:

Sub Base and Base Construction

The material beneath a concrete floor plays a part in how much the concrete above it can support. The sub base weight capacity is largely dependent upon the type of soil and how compactable each soil is. Sand, gravel, and other granular soils are the strongest. More clay-like soils can still be suitable for a sub base, but often have a weight limit of only around 400 pounds per square foot, as opposed to the limits on granular soils that can be up to 2000 pounds per square foot.

Preparing an adequate sub base is an important step in a new concrete flooring installation and offers a chance to increase the live load capacity for your finished surface. In situations where soil is too poor to provide the necessary strength, there are different options available for creating a sub base that is still strong enough to meet your specifications.

Proportions in Concrete Mixture

Concrete is a mixture of several different elements, and the ratios in the final mixture will influence the quality of the finished slab, including the strength. These elements can include:

  • Cement
  • Water
  • Sand
  • Aggregates
  • Admixtures

The cement is essential in determining the strength and load bearing capacities of concrete, based on both the grade of the cement and the amount. The amount is defined by the water to cement ratio. The correct water to cement ratio depends on environmental settings, as well as specifications for a concrete floor.

In general, a lower water to cement ratio is going to be stronger, as well as more durable, than one with a higher ratio. For example, a .50 water to cement ratio often starts at a strain of 4000 psi, while a point .45 water cement ratio can start at a strength of 4500 psi. There is a balance here, however, as too little water yields a concrete mixture that is unsuitable and will be both difficult during installation and may not last as long.

Aggregates in the concrete, such as sand and gravel, can also impact how much weight a concrete slab can bear. Certain admixtures can also be incorporated into the concrete mixture to increase compressive strength or address other factors that impact weight specifications.


Reinforcing a concrete floor with steel bars or another reinforcement solution is one way to increase the strength. The actual load increase depends largely on the position of reinforcement, measurements of the components, and the materials. Based on the necessary end result, we can plan any reinforcement to complement the strength of the concrete.

Concrete Thickness

For concrete flooring, the minimum thickness is 4 inches, from which the 3000 psi rating for a basic concrete install is derived. But an increase in the thickness of the concrete will yield a corresponding increase in its load bearing capacity. As an example, increasing a slab to 5 inches thick can increase the load bearing capacity by almost 50%.

Finding the right thickness for the needed strength without going too high will give you an effective floor without unnecessary expenditures.

Installation and Curing Process

Installation performed by an experienced concrete flooring contractor will yield a stronger floor than lower quality work. Likewise, ideal curing conditions – or failing that, the correct response to less than ideal conditions – will optimize the compressive strength of a concrete slab.

We want to achieve a compact surface with limited permeability, as air voids will reduce the strength of concrete. It was also necessary to have the concrete cure completely on the correct timeline. The contractor can influence this by admixtures in the initial concrete mixture as well as by scheduling correctly and making adjustments based on relevant environmental conditions.

Flooring Finishes and Coatings

Floor coatings applied over concrete, such as resinous flooring, can change the weight specifications or introduce a new set of weight specifications to your commercial floor. Depending on the type of coating, a contractor can consider specifications in combination with the underlying concrete floor and sub base to yield the right load bearing capacity.

Meeting Weight Specifications with Customized Concrete Floors

Achieving the right load bearing specification for concrete floors during the initial installation process will contribute to your business operations. For this reason, all these design features must be carefully calculated down during the planning stages to be sure that the resulting floor will yield the right results.

Colorado Concrete Repair has installed concrete floors and other commercial flooring solutions that meet even the most stringent requirements. We are able to adjust all applicable specifications that affect compressive strength and load bearing capacity, as well as any other requirements that your commercial or industrial property has for new flooring.

We outline these specifications in our project contract so that you have a clearer idea of how we are going to design and install your floor, and can be assured that the results will stand up to many years of daily business operations. Learn more about how we can meet your needs through an initial conversation with our team. Contact us today to get started.