What’s The Average Cost Of A Concrete Slab Per Square Foot?

A concrete slab, which consists of a flat structure made of concrete, is something many homeowners find themselves needing. Perhaps you are looking to protect your cars in the winter months with a garage or carport. Or maybe you are looking to create a fun patio space in your backyard. Even additions to a home like a 4-seasons room can mean learning about and installing a concrete slab.

Like all home improvement projects, a budget is a good place to start. The cost of concrete slab is probably one of the first questions that pops into your mind. Here, we will outline all the various types of concrete slabs, what they will cost you, and how to get started on this type of project.

How Much Does A Slab Of Concrete Cost?

The cost of a concrete slab is between $4 and $8 per square foot, for an average of $6 per square foot. Keep in mind that this is the full cost for materials and labor combined. The materials alone cost about $4 per cubic foot. What’s the difference between a square foot and a cubic foot, you ask?

A square foot is calculated by measuring the width times the length of a one-dimensional surface. Cubic feet are determined by measuring the width times the length times the height of an object. This means square feet is a measure of area and cubic feet is a measure of volume.

While pretty much any new structure you create will need a concrete slab, different types of structures are required to have different levels of thickness. Check with your local municipality regarding the building codes for your specific project before moving forward.

Cost Of Precast Concrete Slab

When concrete is cast in a reusable mold, cured, and then taken to the construction site, it is called a “precast concrete slab.” Beams and walls that are standard sizes across many different construction projects are often made this way. Precast concrete slab costs $20 – $30 per square foot.

In contrast, when concrete is poured and cured at a specific construction site, it is called “cast-in-place concrete.” As you might imagine, cast-in-place concrete is required for unique, non-standard shapes and sizes. 

Factors That Affect The Cost Of A Concrete Slab

There are a variety of factors that affect the costs of your concrete slab. These include preparing the land, the grade of the concrete, the thickness, the finish, and any reinforcements you might need for your project.

Since there are so many variables, there are often a wide range of prices depending on which contractor you hire for the job. Before you choose a concrete contractor to work with, you may want to compare quotes from several contractors on HomeAdvisor since the cost of a concrete slab can vary.

Land Preparation

The amount of land preparation required for a concrete slab can greatly affect the labor costs associated with your project. Consider the amount of time and effort it would take to clear a forest of trees and grade the land on a hill to get it ready for pouring a concrete slab. Now, compare that to pouring a concrete slab on flat land that is naturally free of trees and other obstacles. You get the idea.

Grade Of Concrete

The grade of a specific concrete is determined by the strength and durability of the mixture of materials used to make the product. Standard concrete, for example, is made of a mixture of water, cement, and aggregate (gravel or crushed rocks). This is typically sufficient for common projects like sidewalks, driveways, and patios.

In contrast, ultra-high-performance concrete is made with extra additives like quartz as well as fibers that make it super strong and durable. In fact, ultra-high-performance concrete can withstand over 17,000 psi without the addition of rebar (more on rebar later).

There are a number of other options on the strength and durability spectrum in between standard concrete and ultra-high-performance concrete. These include products like high-strength concrete and high-performance concrete.

Stamped concrete: It’s a concrete that’s “stamped” to create patterns, resembling stone or brick. Stamped concrete costs are typically more expensive because it’s a multistep process that’s time intensive. The concrete is poured, colored, stamped, and then left to set. It’ll also typically require a sealer to maintain the pattern.

The options don't stop there either. Other specialized forms of concrete include glass concrete (made from recycled glass), asphalt concrete (used mainly for roads), permeable concrete (water can pass through), and self-consolidating concrete (no cement mixer required).

Thickness

Concrete slabs can range from 4 – 8 inches and the thicker the concrete, the more expensive it will be. Here’s a breakdown:

Concrete Cost by Thickness

Finish

Finishes can add durability and longevity to your concrete slab. They can also add your own personal flair. The possibilities are plentiful and choosing the best option for your project depends on how you want the finished product to look. It also, of course, depends on how much you want to spend.

A standard finish will seal and protect the concrete but not change the look at all. The cost to finish a concrete slab this way is $4 – $8 per square foot. For more advanced finishes, the cost goes up.

Textured, stenciled, colored or bordered concrete can provide a tasteful, aesthetically appealing finish. You can even take it up another notch with engraved, scored and color-stained concrete. You can even take it to another level of unique design with hand-crafted design techniques, chemical stains and saw-cut designs.

Here’s a breakdown of cost by finish:

Concrete Cost by Finish

Reinforcements

Depending on the type of project you are working on and the type of concrete you use, reinforcements might be required. These are intended to increase the strength and durability of the concrete.

For example, rebar (a steel bar) or wire mesh are often installed with driveway concrete to increase the weight they can handle. The rebar increases the strength to accommodate cars and other vehicles sitting on the concrete slab for extended periods of time. The wire mesh is intended to hold the concrete slab together and evenly distribute weight to prevent cracking.

Another example of reinforcement is adding a vapor barrier to your concrete slab. This keeps out moisture that can lead to mold and rot in the structure built on the concrete slab. This is a common practice for houses built on a concrete slab instead of a traditional basement foundation.

Here’s a list of all the possible reinforcements you can add to your concrete slab. Keep in mind that using any type of reinforcement will increase the overall cost of both materials and labor. 

• Installing wire mesh or rebar
• Installing insulation
• Adding a vapor barrier
• Creating a thicker slab or thicker edges

Average Cost Of Concrete Slab By Size

As you can see, the variables are plentiful when it comes to designing and installing your concrete slab. This might leave you a bit dizzy when trying to calculate cost. You likely know how much space you need to cover, but not which “extras” are required. Do I need rebar? Glass concrete sounds cool, but what are the drawbacks? These might be some of the questions swirling around your head.

To make sense of it all, trust the experts. Talk to a few different concrete slab contractors and share your vision with them/ They should be able to give you a number of different options that meet your goals (and your budget). For now, here is a general breakdown of what you might expect to pay for your concrete slab depending on the size.

Concrete Slab Total Cost

Average Cost Of Concrete Slab By Application

As previously mentioned, the type of project you are working on has cost implications as well. A concrete slab for RV parking, for example, will need reinforcements or a high-quality concrete to withstand heavy objects. In contrast, a patio may not need to withstand much weight at all. Here’s a breakdown of the amount you can expect to pay depending on what type of project you are undertaking.

Concrete Slab Cost by Application

Now that you know the approximate cost for each of these projects, let’s look at what each of them entails.

Cost Of Concrete Slab For Patio

A simple concrete slab for a patio is all you need to start enjoying your outdoor space with barbecues and other get-togethers. While a simple, 400-square-foot slab will cost about $3,100, it will be more expensive if you want it stamped with patterns.

Cost Of Concrete Slab For A Shed

The $480 estimate provided above assumes for an 8-by-10-foot space with a 6-inch thickness. This should be sufficient for most sheds but be sure your slab is large and durable enough to accommodate the weight of the shed you are planning to build (as well as the items you are planning on storing in it).

Cost Of Concrete Slab for Garage

If you use the same 6-inch concrete thickness for a garage slab but a larger area (24 feet by 24 feet) to accommodate two cars, you are going to pay around $3,460. If you want to finish the garage with epoxy to smooth the surface and increase the longevity, that is going to cost you an additional $1,500 to $3,000.

Cost Of Concrete Slab For A Driveway

A 16-foot-by-38-foot concrete driveway is going to cost you roughly $3,000. Not ready to spend that much? Consider a gravel driveway, which will only cost you about half of that ($1,500).

Monolithic Slab Foundation

When a single pour of concrete is done to create a large concrete slab, this is called a monolithic slab. This is a popular approach because it requires less labor than more uniquely shaped concrete pours. Expect to pay $4,600 – $20,000.

Cost Of Concrete Slab For A Car Parking Pad

A 6-inch thick, 10-by-20-foot parking pad will run you about $1,200. Keep in mind that parking pads are not always allowed by local municipalities, so be sure to check on that before proceeding.

Cost Of Concrete Slab For A RV Parking Pad

An RV parking pad will require more reinforcement or higher quality concrete than a parking pad. This is to accommodate the weight difference between a car and a RV. A 6-inch-deep RV pad that measures 6-by-40-feet costs about $3,840.

Professional Vs. DIY Concrete Slab

Pouring concrete is a difficult task that’s best left to those with experience. If you are an avid DIYer who likes to save money by doing things yourself, you may be tempted to try and handle the job on your own.

Think twice before doing this. Mixing, pouring and framing concrete requires experience and expertise. It also requires substantial equipment that can be difficult and costly to rent or buy.

Concrete Slab FAQs

Hopefully by now you have a good understanding of the ins and outs of concrete slabs. That said, other questions often arise. Let’s take a look at some frequently asked questions about concrete slabs.

Do concrete slabs require maintenance?

If you want your concrete slab to last as long as possible, some maintenance is required. Clean away dirt and other debris regularly and make sure to clean up any toxic spills, like oil from a car. Repairing cracks and applying sealing to your concrete slab are other ways to extend its life.

How long does a concrete slab last?

A long time. Oh, you wanted a more specific answer? Well, concrete slabs can last 30 – 100 years. How long your slab will last depends on a variety of factors including how you use it, how you maintain it, and how harsh the weather is where you live.

Can I pour a concrete slab myself?

It’s not impossible, but it’s also not advisable. It’s a complicated process that often requires heavy, specialized equipment. Do you have a cement mixing truck in your garage? You get the idea.

Is a concrete slab the same as a cement slab?

No. Cement is a component of concrete. Concrete is created by mixing cement, water and an aggregate (usually crushed stone, sand or gravel). Cement can work by itself, but turning it into concrete makes the surface much stronger and more durable.

How much does a concrete slab for a house cost?

As noted above, this depends on a number of factors. While most houses have a basement for a foundation, many do use a concrete slab. The factors that affect cost are concrete type, size, thickness, and the process for clearing the land before installing or pouring the slab.

The type of house factors into the price as well. Some houses require more reinforced concrete or a higher quality mix. Others (like mobile homes) weigh less and don’t require concrete that is quite as expensive. Basically, everything comes to how much weight the concrete needs to support and how long it needs to be able to support that weight.

What’s the cost of a 30-by-30 concrete slab?

That largely depends on the thickness and type of concrete being used. The range can vary based on all of the factors previously mentioned (and more), but the average costs of a 30-by-30 concrete slab is about $5,400.

The Bottom Line

The cost of a concrete slab has a wide range based on many different factors. The type of concrete, thickness, reinforcements needed, and labor costs have a big effect on price. In addition, creating a unique style like carvings or a unique shape that requires specialized pouring can increase costs.

Selecting the right concrete starts with deciding which type is best for the project you are undertaking. For example, standard concrete will work fine for a patio, but stronger and more durable concrete will be required for building a house or garage.

Before you get started, be sure to shop around. The contractor you select can have a big impact on the quality of work as well as the cost. Do your research, get multiple quotes, and never stop learning. You can also browse our blog to learn other homeowners tips.