How Much Does a 40×40 Concrete Slab Cost? | Pricing Important Factors

Building a 40×40 (1600 square foot) barndominium may cost $48,000 to $128,000. The foundation of the building accounts for a relatively large portion of the construction costs.

So, how much does a 40×40 concrete slab cost? You may spend between $6,400 and $12,800 on a 40×40-foot foundation. However, concrete slab costs may vary in various features, including different thicknesses and materials for reinforcing the foundation.

Basic Features of a 40×40-Foot Concrete Slab

The estimate of $6,400 to $12,800 assumes that you want a concrete slab with standard features, including:

• 3,000 PSI concrete poured to a depth of six inches
• 2×6 boards to create a wood form around the slab
• Fiber mesh material to reinforce the concrete
• Laborers to handle the pouring and finishing

Choosing different options from the features listed above may result in different costs. For example, pouring a thinner slab costs less while replacing the fiber mesh with reinforced wire increases the cost.

How Much Does a 40×40 Concrete Slab Cost?- Factors That Determine the Cost

The biggest factor is the size of the foundation. A 40×40-foot slab includes 1,600 square feet of space. As estimates are based on the total square footage, a larger foundation costs more to pour. Other features that influence the cost include:

• The condition of the worksite
• The thickness of the slab
• Optional features
• The cost of material and labor in your region

If the worksite is not properly prepared, you may need to pay for site preparation work. Clearing vegetation and leveling the ground can cost between $0.60 and $1.25 per square foot.

The thickness of the slab is another consideration, as the average of $4 to $8 per square foot is based on the installation of a six-inch slab. A four-inch slab saves about $0.74 per square foot compared to a six-inch slab.

You can also choose from a variety of optional features, including:

• Vapor barriers
• Thicker edges
• Wire mesh
• Styrofoam layer
• Textured concrete

Some of these options are not common when pouring a foundation. For example, you do not need textured concrete, as you will likely add flooring. Styrofoam is used to increase the insulation of the barndominium but is not necessary for most regions.

Recommended options include a vapor barrier, thicker edges, and wire mesh. Increasing the thickness of the edges up to 12 inches improves the overall strength of the foundation.

Adding a vapor barrier increases protection against moisture, reducing the risk of cracks. Using a wire mesh instead of a fiber mesh also enhances the durability of the foundation.

Along with the features discussed, the region where you live may influence the total cost. Some of the states in the Midwest, south, and southeast have lower wages and building costs compared to states in the northeast and the west coast.

How to Estimate the Cost of a 40×40 Concrete Slab

You should first decide whether you want to pour the concrete slab or hire someone. For a DIY project, choose the thickness of the slab:

• 4 inches – $2.83
• 5 inches – $3.20
• 6 inches – $3.57

You may also want to include the features discussed when asking How Much Does a 40×40 Concrete Slab Cost? These include such as a vapor barrier, thicker edges, and wire mesh. These optional features add another $1.90 per square foot to the total. 

For example, if you plan on pouring a four-inch foundation, you may pay about $4.73 per square foot ($2.83 + $1.90 = $4.73). For a 40×40 slab, you may pay about $7,568. To get an estimate of the cost of pouring concrete, you can use a concrete slab calculator to help determine costs.

Hiring someone else to pour the same type of foundation brings the cost closer to $8 per square foot. For a 1,600-square-foot foundation, you can expect to receive quotes for about $12,800.