Its usage was generally decorative and most commonly it served as a pavement, though it was also used as an infill pattern in walls. Unless the elements run horizontally and vertically, it is inherently weak, since the oblique angles of the elements tend to spread the pattern horizontally under compression.
Herringbone work, particularly in stone, is also used to make firebacks in stone hearths. Acidic flue gases tend to corrode lime mortar, so a finely-set herringbone could remain intact with a minimum of mortar used. Usk Castle has several fine exampled. The herringbone pattern produces opposing shear plane faces, increasing the relative surface area and therefore rendering it a more sound design for mortar and brick.
Opus caementicium roman walls