A corner break is a crack that intersects the joints at a distance less than or equal to one-half the slab length on both sides, measured from the corner of the slab. For example, a slab measuring 3.5 by 6.0 m (11.5 by 20.0 ft.) that has a crack 1.5 m (5 ft.) on one side and 3.5 m (11.5 ft.) on the other side is not considered a corner break; it is a diagonal crack. However, a crack that intersects 0.5 m (4 ft.) on one side and 2.5 m (8 ft.) on the other is considered a corner break. A corner break differs from a corner spall in that the crack extends vertically through the entire slab thickness, whereas a corner spall intersects the joint at an angle. Load repetition combined with loss of support and curling stress usually causes corner breaks.