How Much Does a Concrete Slab Cost?

A concrete slab is one of the simplest construction projects you’ll ever commission. Whether you are installing a driveway, a patio, or the foundation of a shed, a concrete slab is designed to provide a solid base for whatever you’re working on. Despite the relative size of a concrete slab, the ease of pour and the simplicity mean that it may not be as expensive as you may think.

This guide will show you the different options available to you. It may be that the home improvement project you’re dreaming of is actually more affordable than you assumed.

THE OVERALL COST

Overall, you can expect to pay somewhere around $6.60 per square foot for a slab of concrete, and generally, the price will be within the range of $4.34 and $7.73 per square foot. Of course, concrete is not a two-dimensional product but a three-dimensional one, so you’ll need to factor in the thickness of the concrete you need in order to get an overall price.

In addition, depending on what you’re planning on using the concrete for, you may need to add in some extras, such as a mesh wire, a vapor barrier, or even styrofoam insulation. In each of these cases, the cost of the concrete slab will increase. As such, you can end up paying somewhere in the vicinity of $9.29 to $10.04 per square foot.

The below guide will go through some of the breakdowns of the costs involved so that you get a rough idea of the price, depending on the specifics of your project. Whatever you need a concrete slab for, it’ll fall between the range listed above; precisely where it fits in that range will be outlined below.

How Does Size Affect the Cost?

There is little or no economy of scale when it comes to buying a concrete slab (unless you are ordering concrete on a truly industrial scale, such as building a warehouse or an entire apartment complex). For most residential uses, you are looking at paying an average cost per square foot of around $6.60. The table below shows a breakdown of some of the most common dimensions of a concrete slab.

Dimensions	Total Square Footage	Low Cost	Average Cost	High Cost
8 x 8	64	$278	$422	$495
10 x 10	100	$434	$660	$773
12 x 12	144	$625	$950	$1,113
15 x 15	225	$977	$1,485	$1,739
12 x 20	240	$1,042	$1,584	$1,855
20 x 20	400	$1,736	$2,640	$3,092

What you’ll notice is that the average prices tend to be near the higher end of the range. This demonstrates how hard it is to get the lowest possible cost for concrete. In reality, this is because of the relative rarity of these low-cost options – you’ll need to do some serious shopping around, as well as living in a low cost of living area in order to get the bottom line prices.

Of course, getting a few different quotes for any work will help keep your costs down, but the above table will give you a more than useful ballpark to play with. Even if you’re looking at dimensions not listed on the table, you can use the total square footage as a guideline.

What Type of Slab Will You Need?

One of the biggest determinants of cost is the purpose of your concrete slab. Its intended use will shape the way that it has to be poured, any extra features, and the required thickness of the slab. Below are listed some of the most common types of concrete slabs.

Patio

Concrete patios are one of the most common concrete slab uses. Generally, for a concrete slab patio, you’ll pay between $4.40 and $16 per square foot. This leads to the following cost breakdown based on the most common square footages:

Size of Patio (square feet)	Price Range
80	$352 to $1,280
100	$440 to $1,600
120	$528 to $1,920
140	$616 to $2,240
160	$704 to $2,560
180	$792 to $2,880
200	$880 to $3,200

Driveway

Concrete driveways – along with patios – are the most common residential uses of concrete slabs. Because driveways have to deal with the weight of cars and trucks, they need to be structurally sound and to be reinforced to support the weight. They also tend to be over a larger area than a patio (the average driveway is around 480 square feet, whereas the largest patios are around 200 square feet).

A 480 square feet driveway will likely cost somewhere between $2,880 and $6,720.

Shed Foundation

If you’re building a shed or similar outbuilding, then you may need to use a concrete slab foundation. For a standard size shed, you’d need a slab of between 4 and 6 inches in thickness (for more information on how thickness impacts cost, see the section below).

Depending on the specifics of your shed foundation, you can expect to pay the below prices:

Dimensions of Slab	Slab Thickness	Reinforcement*	Average Total Cost
10 x 10	4 inches	No reinforcement	$535
10 x 10	6 inches	No reinforcement	$619
10 x 10	4 inches	Yes reinforcement	$620
10 x 10	6 inches	Yes reinforcement	$704

*Reinforcement refers to standard mesh wire and vapor barrier.

Garage Floor

As with a shed foundation, a garage floor price is contingent upon the thickness, and the reinforcements required. As well as the mesh wire and vapor barrier, garage floor slabs also contain insulation – usually made from a form of styrofoam. This allows the space to stay warmer so that it can remain usable space.

Dimensions of Slab	Slab Thickness	Reinforcement*	Average Total Cost
24 x 24	4 inches	Yes reinforcement	$4,291
24 x 24	5 inches	Yes reinforcement	$4,539
24 x 24	6 inches	Yes reinforcement	$4,775

*Reinforcement refers to standard mesh wire and vapor barrier, as well as styrofoam insulation.

Foundation

Of course, one of the uses contractors have for concrete slabs is to build entire home foundations. Although there are several different types of foundations, a monolithic slab is one of the most common because of the relatively low cost of labor and speed of pouring.

For a monolithic concrete slab foundation, you’ll most likely pay somewhere between $4.50 and $14 per square foot. Obviously, this is a cost you’ll be unlikely to have to pay as a homeowner (as it will be bundled into the overall cost of your home).

How Does Thickness Affect the Cost?

As mentioned above, concrete is a three-dimensional structure, meaning it is often preferable to think of it by volume rather than by square foot. The reason for the enduring usage of square footage is that concrete slabs tend to come in one of three thicknesses – 4, 5, or 6 inches.

Generally, the costs for these are as follows:

Thickness	Average Cost per Square Foot
4 inches	$5.35
5 inches	$5.78
6 inches	$6.19

This is obviously a great deal of variance, particularly over larger areas. The table below shows how this can impact different sizes of slabs.

Slab Dimensions	Total Square Footage	4 in. Thick	5 in. Thick	6 in. Thick
8 x 8	64	$342.40	$369.92	$396.16
10 x 10	100	$535.00	$578.00	$619.00
12 x 12	144	$770.40	$832.32	$891.36
15 x 15	225	$1,203.75	$1,300.50	$1,392.75
12 x 20	240	$1,284.00	$1,387.20	$1,485.60
20 x 20	400	$2,140.00	$2,312.00	$2,476.00
20 x 40	800	$4,280.00	$4,624.00	$4,952.00
30 x 30	900	$4,815.00	$5,202.00	$5,571.00

You can use the above figures to provide you with a ballpark for your own home project. For slabs much larger than those listed above, you may need to get a custom quote. However, generally, you’ll be working with the size and dimensions listed above. A professional will be able to give you advice on the specific depth of slab you need for your project, which is sometimes determined by local building code.

If you need to buy a concrete slab,

it’s usually not one of the most glamorous purchases you’ll ever make. However, the good news is that it actually may not be as expensive as you may think. Generally, you’ll pay somewhere between $500 and $5,000 for a concrete slab, with a few extreme exceptions at either end of the price bracket.

Of course, it’s always best to consult with a professional before making any decision about purchasing; you should get a few quotes in order to get the best price. However, this guide will help show you what those quotes should roughly be. That may tell you if the home project you have in mind is even financially viable in the first place.