header
A brick that is laid sideways (on its largest face), for example at the top of a wall or within the brickwork, with its smallest side showing (oriented so that that side is wider than it is tall).
header: brick laid to show its narrow end
A header is a brick positioned so that its shortest dimension runs through the thickness of the wall, leaving only the narrow end visible on the wall face. In a standard brick measuring roughly 215 mm long, 102 mm wide, and 65 mm tall, a header shows a face of approximately 102 mm by 65 mm. This orientation contrasts with a stretcher, which displays the brick's longest face.
Headers serve a critical structural function: they tie the outer and inner wythes (vertical layers) of a cavity wall or multi-leaf masonry together. In Flemish bond, the traditional decorative pattern, headers and stretchers alternate in each course to create mechanical interlock and distribute loads across the full wall thickness. In English bond, entire courses of headers run perpendicular to the wall face. Without headers, two separate wythes can move independently, compromising the wall's integrity and weather resistance.
Placement and Bond Patterns
Headers appear at regular horizontal intervals determined by the bond pattern chosen. In Flemish bond, they occur roughly every other brick in each course and staggered vertically. The frequency affects both aesthetic appearance and structural efficiency. Modern cavity wall construction, which relies on metal wall ties rather than header bricks to tie wythes, still employs occasional headers or brick-ties to maintain the appearance of traditional bonding.
Common failure occurs when headers are omitted from the inner wythe or replaced entirely with ties; this weakens the wall if the ties corrode or were installed incorrectly. Frost action can also damage headers more severely than stretchers because their shorter dimension provides less material to resist ice expansion. Water penetration at the header mortar joint, especially in older structures, can lead to damp transferred from outer to inner leaf.
The term header likely derives from the brick's position at the head or leading edge of the wall thickness, though it has been standard terminology for centuries in English-language masonry. Understanding header placement remains essential for restoration work, structural assessment, and achieving consistent brickwork appearance in conservation projects.