Concrete Slab Thickness Guide
Recommended concrete slab thickness for patios, sheds, garages, driveways, and workshop floors, with rebar and mesh guidance.
Patios and shed floors: 4 inches. Garage floors and standard driveways: 4 to 5 inches. RV pads and workshop floors: 6 inches. All over a 4 inch compacted crushed-stone base with 6x6 W2.9 wire mesh or #3 rebar on 18 to 24 inch centers.
Thickness by use
- Sidewalk: 4 inches
- Patio: 4 inches
- Shed floor: 4 inches
- Garage floor: 4 to 5 inches
- Standard driveway: 4 to 5 inches
- RV or truck pad: 6 inches
- Workshop or shop floor: 6 inches
Reinforcement
Add 6x6 W2.9 welded wire mesh at slab mid-depth for a patio or sidewalk. Use #3 rebar on 18 to 24 inch centers for driveways and heavier slabs. Fiber-mesh admix reduces plastic shrinkage cracks but does not replace structural steel.
Base and drainage
Under every slab: 4 inches of compacted 3/4 inch crushed stone (dense-grade aggregate). Slope the finished slab 1/8 to 1/4 inch per foot away from any structure to shed water.
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Last reviewed . Educational estimates only; local conditions and codes take precedence. Consult a qualified professional for site-specific decisions.