How much rebar do I need for a slab?
For a grid of rebar running both directions in a concrete slab.
Rebar (20 ft sticks)
31 sticks
Estimated material cost
Rebar
31 x $$13.00 per 20 ft stick
$403
Chairs
100 x $$0.40 per chair
$40.00
Typical store prices before tax and delivery. Change any price to match your store.
How to measure
Measure the slab's length and width and choose your grid spacing.
Tips from the field
- Includes 10% for overlaps. Overlap bars about 40 times the bar diameter, around 20 inches for #4 bar.
- Set rebar on chairs so it sits in the middle of the slab, not on the ground.
What you'll need
Common questions
What size rebar for a driveway?
#3 or #4 rebar in an 18 to 24 inch grid is common for residential driveways.
How much should rebar overlap?
About 40 times the bar diameter, around 20 inches for #4 bar.
Where should rebar sit in a slab?
In the middle of the slab's thickness, held up on chairs, not lying on the ground.
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