Cost of a 30×30 Concrete Slab 4 Inches Thick

cost of 30x30 concrete slab 4 inches thick

Constructing a 30×30 feet concrete slab that’s 4 inches thick is a task that requires meticulous planning, understanding of material costs, and a recognition of labor charges. Whether it’s for a new garage, patio, or shed foundation, this article sheds light on the various cost components you should consider.

1. Materials: Breaking Down the Basics

  • Concrete: Prices vary depending on your region, but on average, concrete costs between $90 and $150 per cubic yard. Given that a 30×30 feet slab 4 inches thick requires approximately 11 cubic yards of concrete, the material costs alone can range from $990 to $1,650.
  • Reinforcement: For a slab this size, you’ll likely want reinforcement to ensure durability. Steel rebar or mesh, typically priced between $0.10 to $0.20 per pound, can add to the overall material costs.
  • Finishing Materials: Consider costs for concrete sealers, curing compounds, or any surface treatments that you want to apply.

2. Labor: The Backbone of Construction

Labor costs can vary widely depending on the region and the complexity of the job. On average, the labor rate for pouring a concrete slab ranges from $3 to $10 per square foot. For a 900 square foot area (30×30), you’re looking at anywhere from $2,700 to $9,000 in labor costs alone.

3. Site Preparation

Prepping the site is crucial for a stable slab. This might involve:

  • Excavation: Removing grass, topsoil, or any debris.
  • Leveling: Ensuring the site is flat and ready for the pour.
  • Formwork: Creating wooden or metal barriers to shape the concrete.

While some DIY enthusiasts might tackle site prep themselves, professional work can range from $2 to $7 per square foot, bringing another $1,800 to $6,300 to the project’s cost.

4. Additional Factors Influencing Cost

  • Type of Concrete: Specialty mixes or colors can be more expensive.
  • Delivery Fees: Depending on the distance from the concrete plant, there might be an added cost.
  • Weather Conditions: Pouring concrete in adverse weather might require additional materials or methods, which can raise costs.
  • Permits: Some local municipalities require permits for certain types of constructions, which can add to the overall expense.

5. Potential Additional Expenses

Always budget for unexpected costs. For instance:

  • Concrete Pumping: If the truck can’t get close to the site, you might need a pump, which can cost upwards of $1,200 for a day.
  • Expansion Joints: These help control where the slab might crack and can add to the materials and labor costs.


A 30×30 feet concrete slab, 4 inches thick, involves a range of expenses beyond just the concrete itself. Considering all the factors, a safe estimate for such a project might range from $7,500 to $18,000, depending on regional pricing and specific choices. Always seek multiple quotes from professionals and ensure thorough site evaluation to get the most accurate estimate for your project.