Flemish bond
In bricklaying, an arrangement of bricks such that each course consists of alternate bricks having their short sides (headers) and long sides (stretchers) facing outwards, with alternate courses being offset.
Flemish bond: brickwork pattern that ties walls together
Flemish bond is a bricklaying pattern in which headers (bricks laid end-on to the wall face) and stretchers (bricks laid lengthwise) alternate within each course, and the pattern shifts between courses so that headers fall above and below the midpoint of stretchers. A brick is typically 215 mm long, 102 mm wide, and 65 mm high in standard British dimensions; a header presents roughly a 102 mm square face, while a stretcher shows the full 215 mm length. This alternation serves a structural purpose: headers lock the outer and inner wythes of a wall together, preventing them from separating under load or thermal stress.
The pattern creates a visual rhythm of small and large brick faces across the wall surface. In traditional work, mortar colour and joint finish were chosen to emphasise this pattern, making Flemish bond a mark of skilled work. When viewed from above, the offset creates a running bond appearance; when seen straight on, the alternating headers and stretchers produce a distinctive checkerboard that is instantly recognisable on Georgian and Victorian buildings.
Structural and practical considerations
Flemish bond is strongest for walls that are at least one brick thick (about 215 mm in single-width masonry), because the headers physically pass through the wall depth to tie front and back faces together. In thicker walls, multiple wythes are bonded at intervals using headers that span the full thickness. The pattern was the standard for load-bearing brickwork before the 20th century; modern cavity wall construction often uses alternative ties and patterns because outer and inner leaves are now separated and may use different materials.
Bricklayers must maintain course height and stretcher length consistently to avoid forcing headers out of their proper alignment. Deviation creates weakness and looks poor. The pattern is more demanding than simple stretcher bond (all stretchers facing out), which is now common for decorative outer leaves, but Flemish bond remains the requirement for conservation work on period buildings and for solid load-bearing masonry where authentic repair is needed.
The name derives from Flanders, the low-lying region that is now part of Belgium and the Netherlands, which was a centre of brick manufacture and masonry expertise from the medieval period onwards. Flemish builders who worked in England and Northern Europe brought their methods with them, and the bond became associated with their tradition. It remained standard British practice for four centuries.