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How Much Does a 40×40 Concrete Slab Cost in 2024?

A concrete slab is a common fixture in most construction projects. It is versatile and affordable if you want to use it as a floor, driveway, walkway, or roof for your structure. A 40×40 concrete slab can be an ideal flooring option for a barndominium if you want sturdy flooring that’s not as expensive as tiles or hardwood. 

Before you can compute the cost of a 40×40 concrete slab, you need to learn about the different factors that affect the cost, like the slab’s size, thickness, and the building materials that go into it. This article will detail the process of computing a 40×40 concrete slab to help you prepare your budget if you need to make one. 

What Factors Determine the Cost of a 40×40 Concrete Slab?

Multiple factors affect the cost of a 40×40 concrete slab. The most obvious factor is the size of the slab. A 40×40 concrete slab will result in a slab measuring 1,600 square feet. Size is an important factor because you will need more materials to make a large slab. A large slab will also take longer to make, so expect labor costs to be higher. 

Location is another factor you need to consider. Building barndominiums and pole barn homes in remote areas is often more expensive. Why is that? For one, some suppliers charge more when delivering in hard-to-reach areas. It is also common to have fewer suppliers in remote areas, so you might have no choice but to buy materials from the available supplier at a premium. Some contractors also charge more if the site is in a remote location. This is to account for the time they lose when traveling to your location. 

How Much Does a 40×40 Concrete Slab Cost?

Like other construction projects, concrete slabs have different characteristics that influence their costs. This section delves into these characteristics and their importance to costing. 

Per Thickness

You might not know this, but concrete slabs come in different levels of thicknesses. The thickness of a concrete slab will depend on how you plan to use it. The rule of thumb is that you need a thicker slab if it bears heavy loads. Let’s say that you have a garage in your barndominium and that garage houses your cars, a boat, and an RV. These are pretty heavy vehicles, so you need a thick concrete slab to prevent the slab from cracking or breaking under all that weight. A thick 40×40 slab will drive barndominium costs up, but it ensures your garage won’t easily get damaged. 

ThicknessCost per square foot
4 inches $5.35
5 inches  $5.80
6 inches $6.20 
8 inches$7
This table shows the average cost per square foot of a concrete slab in 2023 depending on their thickness (1)


There are some basic tools and materials you need to make a 40×40 concrete slab. You will undoubtedly use these tools, so you need to factor them into your computations. One such tool is a cement mixer. A 1,600-square-foot concrete slab requires a large amount of concrete mix, and getting a cement mixer can help you or your contractor mix concrete easily. You can look for companies that rent out construction equipment per day. Another option is to buy a concrete mixer. This might be more practical if you have other construction projects planned. 

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Inclusion Cost 
Site preparation                $1-$2 per square foot (2)
Concrete Rebar $1.40 – $1.85 per 2 feet (3)
Wire Mesh$0.28 per square foot (4)
The table shows the average costs of concrete slab inclusions in 2023. 

With Additional Features

You might want to add extra features to your concrete slab depending on its intended use. These features can make the slab more durable and attractive. If your floor plan includes a basement and you plan on using a concrete slab floor, you need to add a vapor barrier. A vapor barrier can help prevent moisture from the ground from getting through the concrete slab and into your barndo. Excess moisture in basements is something you need to take seriously, as it can promote mold and mildew growth. Mold and mildew can cause respiratory problems for a building’s occupants. Excess moisture can also damage your furniture and appliances in your basement. 

Features Cost
Vapor barrier $0.50-$0.70 per square foot (5)
Stamped concrete$9 – $20 per square foot, inclusive of materials (6)
Stained concrete$2 – $4 per square foot, staining only (7)
This table shows the average costs of extra features of concrete slabs.

40×40 Concrete Slab Cost Breakdown

Let us now discuss the cost of the individual components of a 40×40 concrete slab. 

Concrete Bag Cost Estimate

You cannot make a concrete slab without using concrete mix, and a bag of concrete mix costs between $4.50 and $27 (9). You might have noticed that we have given you a rather large range of prices. This is because each bag’s cost depends on its size and the type of concrete mix it contains. 

Labor Cost Estimate

It would be best to consider labor rates since a 1,600-square-foot concrete slab is a huge project and might be too challenging to do yourself. Expect to pay between $2 and $3 per square foot in labor charges (10). However, rates can change depending on the contractor you are hiring. Veteran contractors might charge more than less experienced contractors. 

Truck Cost Estimate

It is normal to order wet concrete for large projects as this can help save time and ensure the timely completion of projects. A cubic yard of wet concrete costs between $125 and $133 (11). Some suppliers also have fuel surcharges of between $40 and $50 per truckload, depending on how far the construction site is (8)

How Do You Calculate the Cost of a 40×40 Concrete Slab?

Now that you’re well-versed in the basics of concrete slabs, it’s time to teach you how to compute a 40×40 concrete slab’s cost. You will see some price cost averages to help you compute the cost of your concrete slab in several ways. 

The first thing we need to do is determine how much concrete we need. According to this calculator, you will need 29.63 cubic yards of concrete to make a 40×40 concrete slab that’s 6 inches thick. We will add a 10% wastage allowance, so you’ll eventually need 32.59 cubic yards. According to the National Ready Mixed Concrete Association, one cubic yard of concrete costs $137 (11). This means that 32.59 cubic yards of concrete will cost $4,464.83.

concrete volume estimate for 40x40 slab
Concrete volume estimate for 40×40 slab

We can also compute a concrete slab’s cost by looking at how much each square foot of concrete costs. A 40×40 concrete slab equals 1,600 square feet, and one square foot of 6-inch thick concrete costs $6.20 (1). We will multiply 1,600 by 6.20, and the total cost of your slab is $9,920 or $10,912 with the 10% wastage allowance. 

Should You DIY or Hire a Contractor for Your 40×40 Concrete Slab Project?

We recommend that you hire a contractor to make your 40×40 concrete slab. This is a huge project and almost impossible to do by yourself. A group of workers can work quickly and ensure that you have a concrete slab that’s done correctly. 


Knowing how to compute the cost of a concrete slab is a critical skill. If you are making a concrete slab floor, you can use these computations to ensure you have enough funds to make your slab. It can also help you avoid getting overcharged by your contractor. Even better, you can use these computations to compute not just the cost of a 40×40 concrete slab but any size of slab you will make in the future. Follow our Facebook page for more informative articles about barndominium financing, insurance, design ideas, and DIY tips. 


  1. How Much Does A Concrete Slab Cost In 2023? Homeadvisor.
  2. Cost Of A Concrete Driveway ConcreteNetwork
  3. What Are Common Rebar Prices for Concrete Projects? Angi
  4. How to Compare the In-Place Cost of Wire Mesh Versus Synthetic Fibers ABC Polymer Industries
  5. How Much Does Crawl Space Encapsulation Cost? Angi 
  6. Stamped Concrete Cost For Patios, Driveways & More ConcreteNetwork
  7. Concrete Floor Cost – What You’ll Pay For Polished Or Stained Concrete ConcreteNetwork
  8. How Much Does Concrete Cost? Angi
  9. How Much Does a New Concrete Slab Cost? Angi
  10. How Much Does It Cost to Have Concrete Delivered in Your Area? Fixr
  11. Ready Mixed Concrete Industry Data Survey. NRMCA