How Much Does a Concrete Slab Cost? (2023)

The average cost of concrete slab installation is around $5,400. Most concrete slab projects cost between $3,600 and $7,200. Residential concrete slabs are useful for supporting the weight of cars, sheds, patios, and even houses. The first step of adding a new feature, from building an addition to finishing a basement, is often pouring a concrete slab. We’ll show you what determines this pricing and break down your choices when it comes to pouring concrete.*

*Article cost data via Angi and Home Advisor.

 

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Concrete Slab Major Cost Factors

The most relevant factors to price are the slab’s size, thickness, and means of reinforcement.

Slab Size

The larger the slab, the more concrete it requires and the longer it takes to pour, increasing the price. Thus, concrete slab installation is priced by the surface area’s square footage.

Cost by Size

At an average price range of $4 to $8 per square foot, here’s how cost varies by slab size.

Slab Dimensions	Size in Square Feet	Cost Range
10’x10′	100	$400–$800
12’x12′	144	$576–$1,152
10’x20′	200	$800–$1,600
20’x20′	400	$1,600–$3,200
20’x30′	600	$2,400–$4,800
30’x30′	900	$3,600–$7,200
40’x40′	1,600	$6,400–$12,800

Slab Thickness

In addition to surface area, the slab’s thickness will determine the volume of concrete needed. Concrete is often sold by the cubic foot or cubic yard. For reference, one cubic yard of concrete will cover an area of 81 square feet to a depth of four inches.

Cost by Thickness

Most concrete slabs are between 4 and 6 inches thick, but heavier applications capable of withstanding more weight may require up to 8 inches. You can also request a slab with thicker edges which will add about $1 to $2 per square foot to the following prices.

Slab Thickness (in Inches)	Cost per Square Foot
2″	$4.55
4″	$5.35
5″	$5.80
6″	$6.20
8″	$7.00

Reinforcement of the Slab

Most large or thick concrete slabs require internal reinforcement. For residential applications, wire mesh is often sufficient, but heavy-duty reinforced concrete slabs may require iron rebar. Slabs may also need insulation backing and waterproofing.

Cost by Reinforcement

Here’s how much these reinforcements will add to the cost of a concrete slab.

Reinforcement	Cost per Square Foot
Wire mesh	$0.35
Styrofoam underslab	$0.50
Vapor barrier	$0.50
Rebar	$1.60

 

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Additional Factors Affecting Concrete Slab Cost

Depending on your concrete project’s specifics, you may also encounter the following additional costs.

Concrete Grade

Though some people use “cement” and “concrete” interchangeably, cement is actually an ingredient in concrete. Concrete mix also contains sand and aggregates that make it stronger. Thus, a pure cement slab is weaker and used less often than concrete.

Concrete mixtures are graded with the letter M followed by a number—the higher the number, the more aggregate in the mixture, and the more heavy-duty use it can endure. Most residential projects require M15, M20, or M25 concrete. High-strength concrete mixtures, which go all the way up to M70, are typically used for commercial purposes. Generally, the higher the grade, the more it will cost.

Finishing Materials

If your project is serving as a hidden foundation for another home feature, basic concrete may be sufficient. However, if the concrete will be visible as a concrete floor or patio base, you may want a decorative finish. You can stain or dye the concrete for an additional $6 per square foot on average. The concrete can also be stenciled, textured, or stamped to imitate the look of other materials such as tile, marble, or slate for about $10 per square foot. For around $15 per square foot, you can request multiple colors, patterns, or embossing. On the high end, specialized techniques such as hand-sawing and engraving cost $18 per square foot or more.

Permits

Not all concrete slab installation requires a permit to meet building codes. For example, a simple concrete foundation to support a small shed or outbuilding doesn’t usually call for a permit, but a concrete patio above a certain grade or a concrete driveway above a basement structure usually does. Check with your local building permit office or consult with concrete contractors to determine what you need.

Removing Old Concrete

If you’re replacing a concrete slab, you’ll need to have the old slab demolished and removed. This usually costs between $2 and $6 per square foot, depending on the slab’s thickness.

Repairs

Concrete slabs are highly durable, but they will develop cracks over time. Depending on the old slab’s condition, you may be able to repair it instead of replacing it. Sealing minor cracks with epoxy costs around $0.20 per linear foot. Resurfacing the slab tends to cost between $3 and $5 per square foot.

Subbase Preparation

To improve drainage around a concrete slab and keep it from shifting as it settles, the slab is often installed atop a layer of gravel, sand, or crushed stone that serves as a sub-base. This layer must be compacted and leveled before the concrete can be poured. Depending on what you’re using the slab for, you may want a layer of styrofoam to act as an insulator or a vapor barrier for extra waterproofing. Site preparation costs for a slab will depend on the sub-base material and local labor costs.

Type of Project

Common construction projects often require predictable sizes of concrete slab. Here are some common projects and their average prices.

Project	Average Cost
Shed base	$480
Fire pit	$700
Parking pad	$1,200
Driveway	$3,000
Patio slab	$3,100
Garage floor	$3,460
RV pad	$3,840
Mobile home base	$9,720
Monolithic slab foundation	$12,300

• Shed base: Pouring a simple concrete slab for a tool shed or propane tank can often be a do-it-yourself (DIY) project. The exact dimensions will depend on the size and the weight the slab needs to support, but $480 will get you an 8-inch-by-10-inch slab that’s 4 inches thick.
• Fire pit: A small fire pit with seating around it can usually be poured and furnished for about $700.
• Parking pad: Not all cities allow residences to have parking pads separate from a driveway, so check with your local authorities before planning a parking pad. You’ll pay about $1,200 for a 6-inch slab that measures 10 inches by 20 inches.
• Driveway: The total cost of a concrete driveway will depend on size. You’re likely to pay between $1,800 and $6,000, with an average price of $3,000.
• Patio base: Expect to pay around $3,100 for a 400-square-foot patio, but the project cost will increase if you want to stain, stamp, or emboss the concrete for a more aesthetically-pleasing finish.
• Garage floor: A 24-inch-by-24-inch concrete pad that’s 6 inches deep can serve as the floor for a two-car garage. Because garages are often subject to spilled oil and other chemicals, it’s a good idea to seal the concrete. The total price will run about $3,460.
• RV pad: The concrete pad’s size depends on the RV’s dimensions, but a 16-inch-by-40-inch pad that’s 6 inches deep costs about $3,840.
• Mobile home pad: A full mobile home usually requires a larger, thicker concrete slab with a price of around $9,720.
• Monolithic slab foundation: A concrete foundation is monolithic if it’s installed all in one pour. It costs between $7,000 and $20,000 with a $12,300 average. This project should be overseen by an engineer.

 

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How to Choose the Right Type of Concrete for Your Slab

Concrete types are based on the ratio of ingredients and any additives. Here are the most commonly used in residential slab construction.

All-Purpose Concrete

All-purpose concrete is widely used in the country because it represents a good balance of strength, durability, price, and weight. It’s a uniform mixture of 10% cement, 20% water, 30% sand, and 40% gravel. For DIY jobs, you can purchase bags of dry materials and add your own water, or you can rent a cement mixer. Because this type of concrete is standardized and premixed, it’s the easiest to use.

However, all-purpose concrete is not the best at withstanding pressure or wear and tear and can get slippery. It’s also porous and may stain and erode if not sealed. All-purpose concrete costs about $120 to $170 per cubic yard. It’s most useful for concrete slabs for sheds or patios that bear a moderate amount of weight.

High-Strength Concrete

The amount of pressure that a material can withstand is measured in pounds per square inch (PSI). All-purpose concrete can withstand about 2,500 to 4,500 PSI, but concrete mixtures that withstand 6,000 PSI or more are labeled as high-strength concrete. Because this concrete is stronger, you can use less of it for the same purpose, and it’s better suited to bear the weight of vehicles and large buildings. It’s also less porous and thus less susceptible to chemical and oil spills.

This added durability comes at a higher price, roughly twice the cost of all-purpose concrete. Because it requires skilled installation and a special curing process, it’s not DIY-friendly, so you’ll pay extra in installation costs. It may be necessary for heavy-duty applications such as supporting an outdoor hot tub or forming the foundation for a large home.

Crack-Resistant Concrete

This is essentially all-purpose concrete with additional fibers in the mixture for better binding. It won’t necessarily hold more weight, but it will resist cracking or breaking due to wear and soil shifting. Crack-resistant concrete is a good choice for high-visibility surfaces that don’t need heavy reinforcement but could use some extra durability, including sidewalks, driveways, and patios. It’s a little pricier than all-purpose concrete at about $130 per cubic yard and may require a specialty sealant.

Reinforced Concrete

Here, the distinguishing feature is not the mixture or additives but the mesh or rebar around which the concrete is poured. This gives the slab far more strength so that it’s able to withstand 40,000 to 60,000 PSI. It’s used in building foundations and commercial or infrastructure applications. The trade-off is that it’s heavy and requires maintenance. Foundation repair costs for reinforced concrete are quite high because this type of concrete often requires quick patching.

Precast Concrete

The above types of concrete are all poured on-site, but concrete slabs can also be pre-poured in a factory for greater uniformity. Since precast concrete is cured before it arrives, it makes for quicker construction, and the factory can use various molds and designs to make the slab to your specifications. It must be transported to your location, though, and this will add to the slab’s base cost. Also, the slab is usually transported in multiple parts, which must be installed and joined by professional concrete contractors.

 

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How to Reduce Concrete Slab Costs

To keep concrete slab and foundation costs as low as possible, follow these tips.

• Even if you hire professional contractors for the actual concrete pouring, do as much of the preparation work as possible. This may include landscaping and breaking up and removing old concrete.
• Choose the smallest size and thickness that gives you the support you need.
• Balance budget with durability. You may ultimately waste money by pouring a slab with insufficient reinforcements that need frequent repair.
• Don’t opt for specialty finishes, stamping, or other decorative touches.
• Slabs with curves are more difficult and time-consuming to pour, so stick to straight lines as much as possible.
• If budget permits, finish with sealant to protect your investment.
• Get cost estimates from at least three local contractors before making your choice.

 

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How to Hire a Professional

Hiring a concrete contractor is similar to hiring most other types of building contractors. Here are some things to keep in mind.

• In some states, concrete contractors need a specific license; in others, it’s enough for them to have a general contractor’s license. Check whether your state requires special licensure.
• All contractors should be bonded and insured.
• Check the company’s page on the Better Business Bureau website. You’ll see its BBB rating and accreditation status, as well as any outstanding customer complaints.
• Also look at trustworthy customer review sites such as Trustpilot and Google Reviews and request references.
• Ask what’s needed to prepare the site, particularly if you want to do the preparation yourself to save on labor costs.
• When possible, get an itemized estimate so you know exactly where your money’s going.

 

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Our Recommendation

Concrete slabs often serve as the foundations for important home features and even homes themselves. Thus, it’s usually a good idea to have professional contractors pour your slab. However, smaller projects may be within the purview of some handy homeowners. We recommend learning about different types and mixtures of concrete before taking on this home improvement job.

 

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