Cracks — static or dynamic

Two kinds of crack, two different jobs

Cracking in concrete is common and has to be addressed before a Maverick flooring or lining system is installed. There are two types. Dynamic cracks have movement potential — they widen or narrow over time in response to rolling loads or temperature changes. Static cracks have no movement potential and stay a constant size. Static cracks are very common and usually develop as the concrete cures, from shrinkage. Dynamic cracks also appear during curing, but are usually caused by improper design or execution of the concrete placement — they are not designed into a slab and are not expected to be there.

Working out which one you are looking at

1. 01
   Start with the age of the slab

   Older slabs and buildings settle over time, and as they do the movement potential decreases.

2. 02
   Look at the spacing

   In an older slab, regularly spaced cracks can mean the control jointing was not designed properly and those cracks are acting as control joints.

3. 03
   Inspect the crack itself

   Crack size and signs of loose concrete help identify the dynamic ones. A truly dynamic crack allows differential movement that opens it up, so wheels impact the shoulders and the crack becomes worn and beat up over time.

4. 04
   Watch a load cross it

   It is often possible to feel or see which cracks are moving by watching a fork truck or other rolling load travel over the slab.

5. 05
   Temperature cracks are harder

   Cracks that respond to temperature open in the cold and close in warmer conditions, which makes a single visit misleading.

6. 06
   The quarter-inch rule

   Cracks greater than 1/4 inch are assumed to be dynamic.