Rebar or Wire Mesh in a Concrete Slab?

Both fight the same enemy - cracks - in different ways. Rebar adds structural strength (it lets a slab carry load across weak spots), while mesh holds random shrinkage cracks tight so they stay hairline. Here's how pros choose.

The Quick Rules

• 4-inch patio or walkway: 6x6 wire mesh is standard. Cheap, fast, right-sized.
• 4-5 inch residential driveway: mesh minimum; #4 rebar on 18-24 inch grid if garbage trucks or RVs will cross it.
• 6-inch structural slab, garage floor, hot tub pad: #4 rebar at 18-24 inches on center, both directions.
• Footings and walls: always rebar, sized by code - never mesh.

The Details That Matter More Than Which One

Whatever you pick, it works only if it sits in the middle of the pour. Mesh laid on the ground ends up at the bottom of the slab doing nothing; use dobies or chairs to hold it up. Rebar at 3 inches from the surface rusts and pops; keep 2 inches of cover. And joints - saw-cut within 24 hours at 24-30x thickness spacing - do more crack prevention than either reinforcement.

For a Full Spacing Chart

Exact grid dimensions per slab size and load live in our rebar spacing guide.