Before building a barndominium, you need a foundation. Most barndominium builders choose to build on a concrete slab due to its durability and affordability.
So, how much does a 100×100 concrete slab cost?
A 100×100-foot concrete slab may cost $40,000 to $80,000. These estimates are based on the average price of $4 to $8 per square foot for a concrete foundation. With a median price of $6, a 100×100 (10,000 square foot) concrete slab may cost about $60,000.
Depending on the options you choose, the cost of your concrete slab may not match the national average. Here is a closer look at the costs of pouring a 100×100-foot concrete slab.
What Do You Get with the Average 100×100 Concrete Slab?
The average of $6 per square foot is based on a concrete slab with standard features. With a standard 100×100 concrete slab, you can expect the following features:
- 3,000 PSI concrete measuring six inches deep
- 2×6-inch lumber for erecting a wood form (wood frame)
- Rebar lining the inner perimeter for extra support
- Fiber mesh reinforcement for increased durability
- Contractor, labor, and equipment
Thinner slabs and slabs with extra features are also available, which can impact the total cost. Here are some of the options that change the average cost of a concrete slab:
- The thickness of the slab foundation
- The use of additional materials or features
- The cost of materials and labor in your area
- Preparing the site for the foundation
The cost of labor and materials in your area may vary from the national average. Less expensive states are often found in the South and the Midwest, whereas more expensive states are out West and in the Northeast.
Preparing the land for your foundation also adds to the cost of the project. Vegetation, trees, soft land, and other features may require extra site preparation work.
Does Thickness Impact the 100×100 Concrete Slab Cost?
The average cost of a concrete slab is for a six-inch slab. Some foundations are only four inches thick, which requires less material. Here is how the thickness of the foundation impacts the cost of materials:
- Four inches – $2.83 per square foot for materials
- Five inches – $3.20 per square foot
- Six inches – $3.57 per square foot
The materials for a four-inch slab cost about $0.74 less per square foot compared to a standard six-inch slab. With a 100×100 concrete slab, pouring four inches of concrete may save about $7,400.
Concrete Slab Options That May Change the Cost of the Project
If you choose a thinner concrete slab, you may need to reinforce it. Here are some of the most common options for increasing the stability of a concrete slab:
- Thicker edges – $1 per square foot
- Vapor barrier -– $0.50 per square foot
- Wire mesh reinforcement – $0.40 per square foot
These three features can increase the structural integrity of the foundation. However, these features also add $1.90 per square foot to your total. For a 100×100 concrete slab, these features may increase the cost of the project by about $19,000.
Should You Hire a Contractor for a 100×100 Concrete Slab?
A 100×100-foot concrete slab with standard features may cost about $3.60 per square foot instead of $6 per square foot if you decide on a DIY project. Instead of $60,000, the price may be closer to $36,000.
Keep in mind that a 100×100 concrete slab covers 10,000 square feet. Pouring the concrete involves a lot of work and experience. The slab needs to be entirely level, which is more of a challenge when dealing with such a large surface. Hiring a contractor ensures that your barndominium is built on a stable base.