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How Much Does a 20×20 Concrete Slab Cost in 2024?

Concrete slabs have many uses, so you’ll likely need one when you have a construction project. You can use one as a walkway, driveway, or base. If you are building a starter barndominium, you can use a 20×20 concrete slab as a foundation or flooring. 

Estimating the cost to make a 20×20 concrete slab hinges on several factors. You’ll have to factor in how thick and large the slab is. You also need to consider the cost of labor and materials in your location. These are just some of the factors you need to consider if you want an accurate computation of how much your concrete slab will cost.

This article will help you understand the costs of making a 20×20 concrete slab. Knowing these costs will allow you to accurately compute how much your slab will cost to create a reasonable budget. 

What Factors Determine the Cost of a 20×20 Concrete Slab?

Like any construction project, multiple factors affect the cost of making a concrete slab. The primary considerations are the size and thickness of your concrete slab. A large and thick slab will use more materials and cost more. A concrete slab measuring 20×20 feet will result in a total area of 400 square feet. 

You also need to consider your location during computations. If your site is difficult to access, the delivery of building materials might be more expensive. Some areas also have higher labor rates, so expenses might be more substantial. This is important when computing the cost of a concrete slab and how much you need to finance a barndominium

How Much Does a 20×20 Concrete Slab Cost?

Let us now look at the costs of making a 20×20 concrete slab. This section will help you understand which factors drive the cost of making a concrete slab more expensive. 

Per Thickness

Thickness plays a critical role in the cost of a concrete slab. A thicker concrete slab will cost more because it requires more building materials. This doesn’t mean you can just use a thinner slab to save money. Some concrete slabs need to be thick to support the weight they will carry. Examples are concrete slabs used for pole barn home foundations or as flooring for heavy machinery garages. 

There are also concrete slabs with thick edges. A concrete slab floor with thick edges is stronger and makes for a more durable barndominium floor. Imagine a 6-inch thick 400-square foot slab with 8-inch thick edges. It will use more materials than a 400-square-foot slab that’s 6 inches thick all over. 

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 of a concrete slab per square foot in 2023, depending on its thickness (1).


Although cement is the main component of a concrete slab, there are other things that go into making your 400-square-foot concrete slab. These inclusions contribute to the structure and strength of a concrete slab. A reinforcing bar or rebar is an excellent example of inclusion.

When you make a concrete slab, you use rebars to increase the tensile strength of your concrete slab. It also helps a concrete slab resist cracking and breaking. 

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If you plan on making the concrete slab on your own, you will need a one-bag cement mixer. This equipment is more than enough to help you work quickly and ensure that your concrete mix gets a thorough mixing. You have two options when it comes to cement mixers, you can rent one from a rental company, or you can buy one if you need it in the future. 

Inclusion Cost 
Cement Mixer          Prices start at $439 (2)
Concrete Mixer Rental$97 per day (3)
Concrete Rebar $1.40 – $1.85 per 2 feet (4)
Wire Mesh$0.28 per square foot (5)
A table showing the average costs of concrete slab inclusions in 2023.

With Additional Features

If you are making a concrete slab for use as flooring or walkway, you will most likely need one with additional features. Let’s say you want a concrete slab floor for a small barndominium, a bare concrete floor might be too plain. To make it more appealing, you can stain your concrete slab floor to give it color.

Patio concrete slab floors can be stamped to give them more character. You can stamp a concrete slab to resemble wood, tiles, brick, or flagstone. Since these features are not normally found on concrete slabs, you need to pay a little extra to enjoy them. 

Vapor barrier $0.50-$0.70 per square foot (6)
Stamped concrete$9 – $20 per square foot, inclusive of materials (7)
Stained concrete$2 – $4 per square foot, staining only (8)
A table showing the average costs of additional features for a concrete slab in 2023. 

20×20 Concrete Slab Cost Breakdown

Let’s check how much you need to pay for the individual components of a 20×20 concrete slab.  

Concrete Bag Cost Estimate

A concrete mixture is the most important ingredient in making a concrete slab. This is the base of your concrete slab and dictates how durable it will be. Depending on the type of mixture and how large the bag is, one bag of concrete mix might cost between $4.50 and $27 (9)

Labor Cost Estimate

If you are not going the DIY route, you need to take labor expenses into consideration while computing the cost of your concrete slab. Labor rates depend on your location but expect to pay between $2 and $3 per square foot (10). Labor rates will also depend on the experience of the contractor you are hiring since experienced workers often charge more. 

Truck Cost Estimate

If you are not mixing your own concrete, it is best to order pre-mixed wet concrete. This will help you conserve time and ensure that your concrete gets mixed properly. Concrete delivery costs you between $125 and $133 per cubic yard (11). Ask your contractor how much concrete your floor plan requires to avoid ordering multiple times. 

How Do You Calculate the Cost of a 20×20 Concrete Slab?

Let’s look at some price cost averages for a 20×20 or 400-square-foot concrete slab. We’ll show you several computations to give you a better idea when creating your budget. 

The first thing we need to do is estimate how much concrete you need. According to this calculator, a 6-inch thick concrete slab with an area of 400 square feet needs around 7.407 cubic yards of concrete. We will account for wastage, adding 10% to this figure. This means that you need 8.15 cubic yards of concrete.

The National Ready Mixed Concrete Association (12) states that a cubic yard of concrete in 2022 costs around $137. Using these figures, you will see that 8.15 cubic yards of concrete will cost around $1,116.55. 

concrete volume estimate for 20x20 slab
Concrete volume estimate for 20×20 slab

Another way is to compute how much your concrete slab will cost per square foot. Since a concrete slab measuring 20×20 gives you a total area of 400 square feet, you need to multiply this figure by the average cost of a 6-inch thick concrete slab which is $6.20 (1). You will then get the figure of $2,728, inclusive of the 10% wastage allowance. 

Should You DIY or Hire a Contractor for Your 20×20 Concrete Slab Project?

We believe hiring a contractor is the safest way to make a 20×20 concrete slab. An experienced contractor can work faster to prevent delays. An expert can also ensure that you have the correct concrete mixture to guarantee a durable concrete slab. 


We believe that homeowners should know how to compute construction expenses, including concrete slabs. Knowing what goes into your concrete slab and how much each component costs can help you prepare an accurate budget. This will also ensure you won’t get overcharged when you hire a contractor or buy building materials.

Using the computations listed above, you are sure you’re paying the correct amount if you need a 20×20 concrete slab for your property. Make sure you follow our Facebook page to read more articles about barndominium costs, barndominiums, shouses, and other metal buildings. 


  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