Installing a concrete slab has an average price of $4 to $8 per square foot. For a 900-square-foot slab, you can expect to pay between $3,600 and $7,200.
Concrete slabs are flat, horizontal structures made of concrete that serve as the base or foundation for buildings, flooring systems in homes and offices, barns, livestock facilities, and storage areas, creating outdoor spaces such as patios, walkways, and driveways.
Whether you’re looking to install new concrete slabs or reinforce the ones you have, here’s a breakdown of what you can expect to pay for a project.
Factors That Affect the Cost of a Concrete Slab
If you plan on working on your driveway or patio flooring consider that many factors can influence the overall cost of installing concrete slabs.
Size Of the Slab
Concrete slabs come in different sizes; the bigger they are, the more expensive. Here’s a list of slab sizes, how many square feet they cover and their average price:
- 8×8 (64 square feet) ― $422
- 10×10 (100 square feet) ― $600
- 20×20 (400 square feet) ― $2,400
- 30×30 (900 square feet) ― $5,400
- 40×40 (1600 square feet) ― $10,560
Pre-Cast Slabs vs. Poured On-Site
Pre-cast slabs are manufactured off-site concrete slabs. They have an average cost between $20 and $30 per square foot. Since they are manufactured in a controlled environment, they have excellent resistance and quality. Pre-cast slabs can quickly be installed by only being positioned and secured at the construction site.
Poured on-site concrete slabs involve directly pouring and curing concrete at the construction site. The average cost of this process is around $6 per square foot, including labor. This is a cost-effective choice for smaller or with unique requirements projects, as they eliminate transportation costs associated with precast slabs.
The Thickness of the Slab
Thicker slabs need more concrete to cover the larger volume. Since concrete is a major component of the project cost, an increase in thickness leads to higher material consumption and, consequently, higher costs. Here’s a list of average prices by the thickness of the slabs:
- 2 Inches: $4 – $5 per square foot
- 4 Inches: $5 – $6 per square foot
- 5 Inches: $5.50 – $6.50 per square foot
- 6 Inches: $6 – $7 per square foot
- 8 Inches: $7 – $8 per square foot
The concrete grade measures the strength and quality of the material. Concrete is graded with the letter M, followed by a number from M5 to M70. The higher the number, the more aggregate in the mixture, and the greater its durability and higher cost.
High-strength concrete mixtures, up to M70, are typically used for commercial purposes and are more expensive than lower-grade options. However, most residential projects use M10 to M25 concrete.
If you require any upgrades or additional features for your concrete slab, such as decorative finishes, stamping, coloring, or particular patterns, these can increase the project’s overall cost.
Labor costs for concrete slab installation are around $2 and $3 per square foot. Labor costs are influenced mainly by the installation’s complexity, including the slab’s size and shape, slopes or uneven terrain, intricate designs or patterns, and additional reinforcement or structural elements. More complex installations require skilled labor, additional time, and specialized equipment, which can increase the overall cost.
Calculating How Much Concrete You Need
To determine the amount of concrete needed for your slab project, you’ll need to calculate the volume of concrete required. The volume of concrete is calculated by multiplying the slab’s length, width, and thickness. You can help yourself with a concrete calculator.
Here is a list of average cost estimates based on different sizes and thicknesses of concrete slabs:
- 200 square foot slab, 4 inches thick: $800 – $1,600
- 500 square foot slab, 6 inches thick: $1,500 – $3,000
- 1,000 square foot slab, 8 inches thick: $2,000 – $4,000
While the size and thickness of concrete slabs may vary, affecting the overall cost of the project, the budget for the most common construction projects can be estimated. Here’s a list of some projects and their average price for installing a concrete slab:
- Shed Base (80 to 300 square feet) ― $480
- Driveway (160 to 400 square feet) ― $3,000
- Patio slab (100 to 144 square feet) ― $3,100
- Garage floor (240 to 400 square feet) ― $3,460
Homeowners can expect to pay an average of $2.55 per square foot when installing the concrete slabs themselves. If you’re looking to save money on your project, DIY is the way, especially when it is a small project with straightforward slabs and no intricate designs.
However, when it’s a larger project that involves pouring concrete, you may need assistance from a professional.
Working with concrete is a lengthy process that involves site preparation, forming, mixing, and pouring the concrete, troweling, finishing and curing. By entrusting these intricate processes to a professional, you can rest assured that they will be proficiently handled using the appropriate tools, resulting in a timely completion of the project.
How To Save Money on Concrete Slab Costs
Concrete is often considered a cost-effective flooring option due to its durability and longevity. It is relatively affordable compared to other flooring materials, especially for larger areas. Additionally, concrete can be versatile in design options and can be stained, stamped, or polished to achieve different aesthetics.
However, if you’re still looking to save money on your flooring project, here are some tips:
- Work with a concrete mix: Use locally available materials and consider using supplementary cementitious materials (SCMs) like fly ash or slag to reduce cement content.
- Optimize the formwork: Avoid complex shapes or excessive formwork that can increase labor and material costs.
- Prepare the site: Proper site preparation is crucial to avoid costly issues later. Clear the area of debris, vegetation, and any obstacles that may interfere with the concrete pouring process.
- Be careful with over-ordering concrete: Discuss with the supplier to determine the most cost-effective batch size and delivery options.
Concrete slabs offer strength, durability, and versatility, making them popular for various construction projects. Their ability to support heavy loads, resist wear and tear, and provide a stable surface makes them suitable for a wide range of applications in both residential and commercial settings.