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How Much Does a 30×30 Concrete Slab Cost in 2024?

A slab is a structural component made of concrete. It has a horizontal surface, making it an ideal floor, roof deck, or base. You’ll often see it used in construction projects because it can support a building, like a house, barndominium, or garage, when connected to walls, beams, or columns. A concrete slab measuring 30×30 feet can function as flooring for a workshop, storage facility, or single-family barndominium.

Computing the cost of a concrete slab is a skill that every homeowner should possess. When you compute the cost of a slab, you need to consider many variables, like size, thickness, quality of materials, and additional features. This article will help you understand what goes into computing a concrete slab’s cost. We will also discuss the various components of a slab and how they affect the slab’s overall cost. 

What Factors Determine the Cost of a 30×30 Concrete Slab?

Certain elements influence the cost of a 30×30 concrete slab. One major consideration is the size of the slab. A slab that covers a large area will consume more building materials, so it is more expensive. In the case of a 30×30 slab, it will cover an area measuring 900 square feet. 

Inflation and the cost of building materials also affect cost. If there are few suppliers in your area, you might have to contend with costly building materials because suppliers have few competitors. You can shop around and ask for quotes from several suppliers, compare them, and buy from the one that offers competitive prices. 

How Much Does a 30×30 Concrete Slab Cost?

As mentioned, a concrete slab’s cost depends on its characteristics. Let’s analyze each characteristic and examine how they can make your slab more expensive. 

Per Thickness

Concrete slabs come in varying degrees of thickness. Thick concrete slabs are excellent for bearing heavy loads. If you want a metal workshop near your barndominium, a thick slab is more suitable for flooring. It can support the weight of tools, equipment, and supplies without deforming or cracking. A thick slab is more expensive because it requires more materials. However, it can be more practical in the long run because you are assured that it is more durable. A thin concrete slab might break if you use it for heavy loads. This will force you to redo the concrete slab, resulting in more expenses. 

ThicknessCost per square foot
4 inches $5.35
5 inches  $5.80
6 inches $6.20 
8 inches$7
A table showing the average cost of concrete slabs per square foot in 2023, depending on thickness (1)


The term inclusion refers to the common materials, tools, and equipment you need to make a 30×30 concrete slab. One piece of equipment that you absolutely need is a cement mixer. You can work faster using a cement mixer because you don’t need to mix concrete manually; it can also ensure that you prepare the concrete mix properly. Try checking if there is a rental one-bag mixer near you for small and one-off projects. For large projects, like pole barn homes, buying a cement mixer might be more economical. 

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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)
This table shows the average costs of inclusions when making a concrete slab in 2023. 

With Additional Features

Some concrete slabs are more expensive because they have more features. If your floor plan has a concrete slab as flooring for a patio or outdoor kitchen, you might want to use stamped concrete. Unlike regular concrete slabs, stamped concrete slabs have texture. This can help make them safe to walk on even when wet. Stamping concrete can also make it more attractive. Stamped concrete can resemble tiles, bricks, or wood. Using stamped concrete can increase the cost of a barndominium, but it will also increase its value. 

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)
This table shows the average costs of added features of a concrete slab in 2023. 

30×30 Concrete Slab Cost Breakdown

In this section, we will look at the breakdown of the costs of the individual components of 30×30 concrete slabs.

Concrete Bag Cost Estimate

Since you are making a concrete slab, you need to buy a concrete mix costing between $4.50 and $27 per bag (9). This is a big ticket item, especially since a 900-square-foot slab will use a lot of concrete. Take note that the cost of a bag of concrete depends on its size and the type of concrete mixture it contains. 

Labor Cost Estimate

The cost of hiring a contractor is another sizeable item on your list. Labor might cost between $2 and $3 per square foot (10). However, don’t be surprised if a veteran builder demands higher labor rates because they often charge more than their less experienced counterparts. 

Truck Cost Estimate

If you are working on a large project, getting wet concrete delivered is more practical than mixing your own concrete. This can help you save time and prevent delays. Wet concrete costs between $125 and $133 per cubic yard (11). Some suppliers also have fuel surcharges costing between $10 and $50 per truckload (9). Fuel surcharges are additional charges if the delivery area is outside the supplier’s service area. 

How Do You Calculate the Cost of a 30×30 Concrete Slab?

Now that you are equipped with the basic knowledge of the characteristics and components of a 900-square-foot concrete slab let’s compute how much it costs. You will see several price cost averages you can use in computing a concrete slab’s cost using different methods. 

Let’s start by determining the amount of concrete you need to create a concrete slab measuring 900 square feet and six inches thick. This calculator shows that you need 16.667 cubic yards of wet concrete. This figure will become 18.33 cubic yards because we will add a 10% waste allowance. Using data from the National Ready Mixed Concrete Association, we know that one cubic yard of wet concrete costs $137 (10). This means that 18.33 cubic yards of wet concrete costs $2,511.21. 

concrete volume estimate for 30x30 slab
Concrete volume estimate for 30×30 slab

Another method is to compute the cost of concrete on a per-square-foot basis. A 30×30 concrete slab has a total area of 900 square feet. One square foot of concrete costs $6.20 (1). This means that the estimated cost of your slab is $6,138, inclusive of the 10% waste allowance. 

Should You DIY or Hire a Contractor for Your 30×30 Concrete Slab Project?

Although you will save money by going the DIY route, we strongly recommend hiring a professional to help you make a concrete slab. This might be more expensive, but you can be sure that your slab will be durable and withstand stress without breaking. 


Knowing how to compute the cost of a concrete slab is a skill everyone needs to acquire. It can ensure you are not overspending while making a concrete slab. It can also help you avoid getting overcharged when hiring a contractor. Using the computations and information above, you can prepare an accurate budget before making a concrete slab, no matter what size it is. Follow our Facebook page for more informative articles about barndominium financing, floor plans, 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