Herringbone

The Interlocking Concrete Pavement Institute's glossary defines herringbone by the joints, not by a picture: it is a pattern where the joints are “no longer than the length plus the width of the units”, set at 45 or 90 degrees depending on the orientation of those joints to the predominant direction of traffic.

Either angle qualifies as herringbone under ICPI's definition, and neither the glossary nor ICPI's street recommendation ranks one over the other. What differs is the angle the joints make with the direction traffic travels. On a sand-set surface, that angle is fixed when the units are placed in their pattern and compacted into the bedding sand, before the joints are filled.

The Brick Industry Association explains what the pattern does under traffic: “a herringbone bond best distributes horizontal forces across a pavement, reducing the potential for creep”.

Among the patterns BIA names as most popular for clay pavers, herringbone is the one the note singles out for spreading horizontal forces; how patterns with continuous joints compare, and how BIA orients them, is set out under running bond.

ICPI's construction guide recommends herringbone in “all street applications”, because these interlocking patterns provide the maximum load bearing support and resist creep from starting, braking and turning tires; the text read does not extend that line to a residential driveway.

BIA's own summary for clay pavers set on a sand bed says to use a herringbone pattern for pavements subject to vehicular traffic. That line names vehicular traffic rather than driveways, and neither note presents it as a code requirement. Which pattern suits a given property, and how it sits on the paver base below it and against the edge restraints around it, is the installer's or designer's design question, not a rule to look up.

Two neighboring words name a feature of a single unit or a single element rather than a pattern: a beveled edge is the angled top edge ICPI's glossary calls a chamfer, and pool coping is the row of material that forms the top of a pool wall.