While a concrete slab cost varies based on square footage, depth, and vendor used, there are some simple rules of thumb to ensure you get a fair price. Fortunately, our complete guide covers them all. Read on to learn more.
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- What Are Concrete Slabs Used For?
- Concrete Slab Sizes and Types
- Concrete Slab Cost Breakdown
- Average Concrete Slab Costs
- Additional Concrete Cost
How much does a concrete slab cost? Several factors can raise or lower the cost of concrete slabs, including the materials used, slab thickness and size, labor costs, and grading.
There are also special finishes and staining options that can raise the cost of a basic concrete slab considerably.
We break down the cost of concrete slabs (overall and per square foot) in this post. Keep reading to find out how much you’ll pay to have a concrete slab or pad poured.
What Are Concrete Slabs?
The purpose of a concrete slab is to provide a stable, durable base. You can use a concrete slab or pad indoors or outdoors. Today, it is common to use concrete slabs in the construction of ceilings and floors.
In high rise buildings, concrete slabs are hung from steel frames to create the floors and ceilings on each level. In a residential setting, they are commonly used for patios, driveways, and above ground pool bases.
Concrete decks are popular around in-ground pools as they don’t require as much maintenance as traditionally constructed wood decks.
Concrete Slab Sizes
There are many ways to use a concrete slab, and there are three general sizes of slabs to choose from. Each is suitable for a different purpose.
Leaner slabs are the smallest type of concrete slab. They are usually sold pre-fabricated so you can purchase them and place them where you’d like them rather than having them poured on-site.
Leaner slabs are not as thick as other types of concrete slabs, and to cover a large area, you’ll need several of them to piece together.
Unlike larger slabs, you don’t have to have a completely level area when you use leaner slabs. However, for the most stability, a graded and leveled area will create the best conditions.
Medium slabs can be poured on-site or pre-fabricated and purchased. They are, as the name indicates, larger than leaner slabs but still small enough to be bought and carried to the designated area for use.
One of the most common uses for medium slabs is false flooring, where the floor is raised to provide space for pipes, wires, or cables underneath.
Large slabs are the most prominent type of concrete slab. They are so large that they must be poured on-site and cannot be pre-fabricated and purchased. Large slabs are used in many construction and outdoor projects.
Because these slabs are often the base for large structures (like houses, pools, garages, etc.), they must be done by a professional who can ensure the area is graded and level before pouring the concrete.
Concrete Slab Types
Not all concrete slabs are poured at an even thickness. There are a few additional types of concrete slabs that have different levels of strength.
Monolithic Concrete Slab
Monolithic (meaning formed of a single large block of stone) concrete slabs are one, solid piece of concrete. This is the type of concrete slab most of us picture when we think of a slab.
In monolithic slabs, the footing or base of the concrete goes lower than the floor or ground area to make it sturdier. The type of soil, if being poured outside, might make it necessary to reinforce the slab with layers of gravel or aggregate underneath.
Clay or loamy soil makes the slab more likely to settle and crack over time, while sandy or well-drained soil makes a stronger base for a monolithic concrete slab.
Engineered or Post-Tensioned Concrete Slab
Engineered or post-tensioned concrete slabs are a very sturdy type of slab that is crack-resistant. It is similar to a monolithic concrete slab, but it has steel cables running through it.
As the concrete cures and sets, those cables are pulled tight (hence the “post-tensioned” part of the name) and attached on the ends.
The steel cable core of this type of slab is what makes it so strong and durable. It is harder for a post-tensioned concrete slab to settle into the ground and crack because the cables hold the entire slab in a flat, level position.
Slabs With Foundation Walls
Another type of concrete slabs are slabs with foundation walls. These slabs are poured into a pre-built foundation wall, while other types of slabs are poured into concrete forms.
If the foundation walls are very deep, these types of slabs will have post holes or piers to make them sturdier and more durable. With these different sizes and types of concrete slabs in mind, let’s break down the factors that weigh into the overall price you’ll pay for one.
Concrete Slab Cost Breakdown
What factors into the cost of a concrete slab or pad? The overall cost will depend on the following factors:
- Precast or poured on-site
- Slab size
- Slab thickness or depth
- Grading the area
- Cost of materials
- Additional reinforcement materials used (steel cables, mesh, etc.)
A small, precast slab costs much less than a large slab that must be poured on-site after the area has been graded, leveled, and framed out with concrete forms and braces.
Likewise, a 5-inch thick slab strong enough to support a garage is much more expensive than a 2-inch thick slab to create a small patio area.
Average Concrete Slab Costs
Depending on what you’ll be using your concrete slab for, the cost can differ widely. It’s helpful to look at the average cost for a few concrete slab projects to get a sense of the overall cost for your project.
Overall, the average price of a concrete slab is about $2,789. About $400 to $700 of this cost covers the materials required for the project.
Concrete Slab Cost Per Square Foot
The overall cost depends on the size of the slab you need. It’s a good idea to know the average price per square foot for concrete slabs so you can come up with a closer estimate of your total project cost.
On average, concrete slabs cost between $4 to $8 per square foot (this includes labor and materials). The most common price is about $6 per square foot.
The materials required for pouring, curing, and sealing concrete have a cost of about $4 per cubic foot. These materials include special tools, lumber for framing and bracing, screws, gravel, concrete mix, water, edging tools, and sealant.
If you are having your concrete slab stained or printed, the cost of materials will increase. The labor involved in pouring a concrete slab also represents part of the total cost. On average, you can expect to pay about $3 per square foot in labor costs alone.
For a project with an area of 400 square feet, the labor could cost about $1,200 – not counting the cost of the materials. This means a 30 by 30 slab that is 6 inches deep (for a garage) will run you about $5,400 with labor and materials included.
Additional Concrete Slab Costs and Extras
Concrete slabs can be more expensive if they have additional reinforcements or custom options. There are some of the additional costs you might come across when you have a concrete slab poured.
You should also consider the cost of materials that are required but may not be itemized and listed on your bill. Some options may be more or less expensive in your area – these are nationwide averages.
Concrete forms are required to provide a clear frame for the concrete to be poured into and smoothed. Strong concrete forms are what give a slab clean, uniform edges, and overall shape.
Forms are typically large lumber pieces, so enough lumber to build the forms will run about $50 to $100 per project.
If your concrete slab is large, chances are, you’ll want to use a reinforcement to give it additional strength and make it more resistant to cracks. Generally, there are two types of reinforcements used in concrete.
These include steel mesh or rebar. Steel mesh is much more cost-effective at about $0.20 to $0.30 per square foot, while rebar is more expensive and suitable for larger projects at $2 to $3 per square foot.
Concrete is a porous material. So sealing it can help prolong the slab’s life and make it less susceptible to damage from changing or extreme temperatures.
Sealing not only the slab itself but also the expansion joints where two or more slabs meet can make a big difference and prevent debris, weeds, or dirt from building up in between the slabs.
Also, sealing concrete keeps it from being stained and provides more chip-resistance. Expect to pay about $1 to $2 per square foot for concrete sealant.
If you’re looking to customize your concrete slab with a unique finish, stain, or stamping pattern, there will be an additional cost. Smooth finishes can make concrete look almost tile-like rather than dull and porous.
Staining concrete can be done in any color and elevate the look beyond basic concrete. Stamping is another exciting option that can give concrete a different appearance, making it resemble wood, stone, brick, or mosaic.
Expect to pay anywhere from $4 to $8 per square foot for special finishes, stains, or stamping.
Concrete Slab Cost Summary
Concrete slabs vary in price due to size, thickness, area preparation, materials required, reinforcement materials, and several custom or add-on options. A small, 2-inch slab will be much less expensive than a 30-by-30 foot slab that is 6 inches thick.
When you’re trying to estimate the cost of your concrete slab project, it’s helpful to know the average cost and cost per square foot to get the most accurate estimate before you begin working with a contractor.
The average overall price of a concrete slab is about $2,789, and the average price per square foot is $6 (between $4 and $8 per square foot). Much of this cost covers labor because pouring concrete is a time-intensive process.
It’s a tedious project that must be done carefully. Concrete slabs are certainly not cheap, and hiring a professional to pour a concrete slab for you can easily turn into a several-thousand dollar bill.
Ensure you have a clear plan for your concrete slab and hire contractors with a good local reputation for a project like this.