Concrete cost guide
Concrete Garage Slab Cost
A concrete garage slab costs about $7 to $15 per square foot installed, so a single-car slab (around 240-400 sq ft) typically runs $2,800 to $7,000 and a two-car slab (480-720 sq ft) runs $4,500 to $11,000. Garage slabs cost more per foot than a basic patio because they carry vehicles and point loads, so they need a stronger mix, reinforcement, and often thickened edges.
This guide explains the upgrades that separate a garage slab from a simple pad and how each affects price. Use the slab calculator with a 4,000 PSI mix to estimate volume and material for your garage footprint.
Need project-specific numbers? Use the Concrete Garage Slab Cost Calculator.
Last updated June 10, 2026
Typical Cost Ranges
| Item | Typical Cost | Notes |
|---|---|---|
| Single-car garage slab | $2,800-$7,000 | About 240-400 sq ft |
| Two-car garage slab | $4,500-$11,000 | About 480-720 sq ft |
| Thickened edge upgrade | $5-$15/linear ft | Depends on depth and reinforcement |
What Drives the Cost
- Mix strength: Garage slabs commonly use 4,000 PSI concrete to handle vehicle weight and freeze-thaw exposure, costing more per yard than standard 3,000 PSI.
- Thickness and edges: A 4 to 6 inch slab with thickened (turned-down) edges supports walls and vehicle loads, adding concrete at the perimeter.
- Reinforcement: Rebar on a grid or heavy wire mesh is standard under vehicles to control cracking.
- Vapor barrier: A poly vapor barrier under the slab controls moisture migration, important if you will store goods or finish the space.
- Base and grading: A compacted gravel base and proper slope to the door keep the slab stable and draining water out of the garage.
How To Estimate It
- Slab concrete = length x width x thickness / 27
- Edge concrete = perimeter x edge area / 27
Why a garage slab costs more than a patio
Both are flatwork, but a garage slab is engineered to carry rolling and point loads. That means a stronger mix, more reinforcement, thickened edges where walls and wheels bear, a vapor barrier, and tighter tolerances on flatness and slope. Each upgrade is modest on its own, but together they lift the per-foot price above a simple patio.
New garage slab vs replacing an old one
Replacing an existing garage slab adds demolition, disposal, and sometimes fixing the base that caused the original to fail. If the old slab cracked from a weak base or poor drainage, budget to correct that rather than pouring a new slab over the same problem.
FAQs
What PSI concrete is used for garage slabs?
4000 PSI is common for garage slabs because vehicles, point loads, and freeze-thaw exposure demand more strength than light patios.
Does a garage slab need a vapor barrier?
A vapor barrier is commonly used below garage slabs to control moisture, especially where flooring or storage will be affected.
How thick should a garage slab be?
Four inches is typical for a standard garage, with 5 to 6 inches and thickened edges where heavier vehicles or wall loads are involved.
How much does a 2-car garage slab cost?
Roughly $4,500 to $11,000 for about 480-720 square feet, depending on thickness, reinforcement, vapor barrier, and local labor.
Can I pour a garage slab myself?
It is possible for a confident DIYer on a small slab, but large, load-bearing pours with tight flatness and slope tolerances usually justify a finishing crew.