How Much Does a 40×80 Concrete Slab Cost in 2024?

A concrete slab is an even surface made of poured concrete. If you have a major construction project, you will likely need one because it can function as a foundation, floor, driveway, or walkway. If you are building a workshop, storage facility, or large garage, a 40×80 concrete slab is an affordable and durable flooring option. 

To compute the cost of a concrete slab, you need to know its different characteristics. It is also important to learn about the different components of a concrete slab to help you accurately compute its cost. This article explains how to determine the price of a 40×80 concrete slab to help you prepare an accurate budget if you need to make one. 

What Factors Determine the Cost of a 40×80 Concrete Slab?

Several factors influence the cost of a concrete slab. The most crucial factor is the size of the slab. Size matters because the larger the concrete slab is, the more building materials it will require. A large concrete slab is also more complicated and takes longer to make. This means that it will entail higher labor expenses. 

The condition of the construction site also matters. If you want a properly-made concrete slab, you need to make sure you pour concrete on a clean and level site. This means that you must ensure the site is free of stones, weeds, tree stumps, and other debris. If you have enough time, you can clear the site yourself to save money. If the concrete slab goes on a site with old concrete, you must chip out the old concrete, and you might need to hire a professional. 

How Much Does a 40×80 Concrete Slab Cost?

In this section, we will tackle the different characteristics of a concrete slab that can drive its cost. 

Per Thickness

Concrete slabs can be thin or thick. A thick concrete slab will use more materials, making it more expensive. However, it is also more durable and stable, making them ideal foundations or flooring options for pole barn homes and barndominiums. If you are making a 40×80/3,200 square-foot concrete slab for a large garage, a thick concrete slab is ideal because it can support the weight of multiple vehicles. If you plan on using a concrete slab as a pathway in your garden or backyard, a thin slab should do the trick since it will only hold a person’s weight. 

Thickness	Cost per square foot
4 inches	$5.35
5 inches	$5.80
6 inches	$6.20
8 inches	$7

Inclusions

Making a concrete slab requires using some building materials, tools, and equipment. These are called inclusions. We mentioned earlier that you need to prepare the site before pouring concrete, and site preparation is inclusion for large projects. If the site is uneven, a contractor can use fill to level it. If there are tree stumps on the site, the contractor can dig them out, so they don’t affect the concrete slab. This can increase your barndominium costs, but it can help ensure that your structure will have a steady and durable foundation. 

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)

With Additional Features

While most concrete slabs are bare or plain, some have additional features depending on their intended uses. For example, if your floor plan includes an outdoor dining area or kitchen, you can use stamped concrete instead of plain concrete. Stamped concrete resembles wood, brick, or tiles, making it look more eye-catching and affordable. Stamped concrete also has a rougher texture that gives it additional grip. This makes it safer to walk on even when they are wet. 

You also have the option of using exposed aggregate concrete. This type of concrete is also less slippery than polished concrete. Exposed aggregate concrete is a concrete slab with its outer layer removed to expose the aggregates underneath, usually small rocks, coarse sand, or pebbles. These are costlier alternatives and can increase the amount you need in financing a barndominium, but they will also increase your property’s market value. 

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)

40×80 Concrete Slab Cost Breakdown

Let us now take a closer look at the breakdown of a concrete slab’s cost. 

Concrete Bag Cost Estimate

The cost of concrete bags is paramount because it is the chief building material you need. As mentioned, a large concrete slab, such as one measuring 3,200 square feet, will need more materials to complete. A concrete bag costs around $4.50 – $27 ⁽⁹⁾. The cost of concrete bags differs depending on their size and the mixture type.  

Labor Cost Estimate

You might be able to go the DIY route for smaller concrete slabs, but hiring a professional contractor is more sensible in making a 40×80 concrete slab. Labor rates for this kind of project cost around $2 – $3 per square foot ⁽¹⁰⁾. Labor expenses can be more extensive if you are building in an area with higher labor rates. You can also expect to pay more if you hire a veteran contractor since they often charge more than their less experienced counterparts. 

Truck Cost Estimate

One cubic yard of wet concrete costs around $125 – $133 ⁽¹¹⁾. Ordering wet concrete is a more viable option since it is faster than manually mixing concrete. Wet concrete gets delivered using concrete mixer trucks to ensure you get thoroughly-mixed concrete. You should also be aware that some suppliers have fuel surcharges of around $40 – $50 per truckload if your location is outside their delivery area ⁽⁸⁾. 

How Do You Calculate the Cost for a 40×80 Concrete Slab?

Now that we’ve covered the basics of concrete slabs, let’s tackle computing a 40×80 concrete slab’s cost. We will present you with several price cost averages so you can compute the cost of your slab using several methods. 

Let us first determine the amount of concrete you will need. Using this calculator, we know that a 40×80 concrete slab that is six inches thick needs around 59.259 cubic yards of wet concrete. We are adding 10% to this figure as a waste allowance, so you’ll need 65.19 cubic yards of wet concrete. One cubic yard of concrete costs $137, according to the National Ready Mixed Concrete Association ⁽¹¹⁾, so 65.19 cubic yards of concrete costs $8,931.03

Another method is by computing the cost of a concrete slab on a per-square-foot basis. A 40×80 concrete slab equals 3,200 square feet. One square foot of concrete that’s six inches thick costs $6.20, so a concrete slab measuring 3,200 square feet costs $21,824, including the 10% wastage allowance. 

Should You DIY or Hire a Contractor for Your 40×80 Concrete Slab Project?

Although making the 40×80 concrete slab yourself is a cheaper option, we highly recommend hiring a contractor instead. This can help ensure that you have a properly constructed concrete slab. 

Conclusion

Knowing the costs of construction projects is important and concrete slabs are no exemption. You can prepare an adequate budget if you know how to compute costs. This can help ensure you finish your concrete slab on time and with all the required tools and materials at hand. If you want to stay updated about barndominiums, shouses, shipping container homes, and other metal buildings, make sure that you follow our Facebook page. 

References

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