Standard Back Gain is a natural occurrence in the welded wire mesh process that is caused by the heating and cooling of the mesh as it is welded into place. It is more common in wire mesh that is tightly spaced. Standard Back Gain is demonstrated in the drawing below. In the drawing below, sides A, B, and C represent a standard 1/8" trim while side D represents Standard Back Gain.
Please note: that the Standard Back Gain is exaggerated in this drawing to more clearly demonstrate the phenomenon.