When securing building materials, spacer requirements include all of the following, EXCEPT:

Spacer Requirements
The length of spacers must provide support to all pieces in the bottom row of the bundle.
The width of each spacer must be equal or greater than the height.
Spacers must provide good interlayer friction.
If spacers are comprised of layers of material, the layers must be unitized or fastened together to ensure that the spacer performs as a single piece of material.