What this covers
- Garage floor slabs
- Shop and barn slabs
- Pads for sheds and outbuildings
- Large pads on open ground
Big slabs, more joints
A shop slab is mostly a joint layout problem. NRMCA’s guidance: joints no more than 24 to 36 times the slab thickness apart and never more than 15 feet, square panels, and isolation joints around columns and footings.
For columns, NRMCA says to form openings around them and, if the openings are square, turn them 45 degrees so the contraction joints meet at the corners.
Fibers and wire mesh
NRMCA is blunt that wire mesh and reinforcement cannot prevent cracking. Placed correctly, they can keep crack widths smaller.
Synthetic fibers do a different job. NRMCA says fibers at typical rates of 1 to 2 pounds per cubic yard reduce plastic shrinkage and settlement cracks and add toughness and impact resistance, without changing the mix.
Recent shop slabs work
Where Tim pours shop slabs
Questions people ask
Do you pour shop slabs?
Yes. Garage and shop slabs are a separate line on Tim’s service list.
Does wire mesh stop cracks?
No. NRMCA says wire mesh and reinforcement cannot prevent cracking, but properly placed reinforcement can reduce crack width.
What do fibers do?
NRMCA says synthetic fibers reduce plastic shrinkage and settlement cracking and add toughness and impact resistance.