What is Flemish bond?

Flemish bond is a brickwork pattern in which every course alternates headers (bricks showing their short end, 102.5mm face) and stretchers (bricks showing their long face, 215mm face) in a regular sequence. The headers in each course are centred over the stretchers in the course below and above. This creates a characteristic and attractive decorative pattern on the wall face - a square repeat of alternating long and short brick faces. Flemish bond is the dominant bonding pattern in Georgian, Regency, and Victorian brickwork and gives much English domestic architecture its visual character.

What is the difference between Flemish bond and English bond?

In English bond, alternate courses are entirely headers (all bricks showing their short end) and entirely stretchers (all bricks showing their long face). In Flemish bond, every course mixes headers and stretchers. English bond is slightly stronger structurally as the full header courses tie across the full wall thickness more thoroughly. Flemish bond uses fewer bricks per square metre (as the headers appear only every other brick in each course rather than in every other course) and is considered more decorative. English bond was more common in earlier (pre-Georgian) brickwork; Flemish bond became dominant from the 1700s onwards.

What is stretcher bond and when is it used?

Stretcher bond (or running bond) uses only stretcher courses - every brick shows its long face and no headers appear. This pattern can only produce a half-brick-thick (102.5mm) wall, as there are no headers to tie across the thickness. Modern cavity walls use stretcher bond for both the outer facing brick leaf and the inner block leaf, with the cavity between them bridged by wall ties rather than bonded brickwork. Cavity construction, universal since the mid-20th century, does not require the bonded headers of solid wall construction, making stretcher bond the standard for modern facing brickwork.

Why does the bond pattern matter?

In solid (pre-cavity) walls, the bond pattern determines how loads transfer through the wall and how well the wall acts as a single structural unit. A wall laid without proper bonding (all stretchers in a 215mm wall, for example) would simply be two parallel half-brick skins with a mortar fill - significantly weaker than a properly bonded wall. In modern cavity walls, the structural argument for traditional bonds is less important, but the appearance is critical: Flemish or English bond on an extension wall that abuts a Victorian Flemish bond property is a standard planning expectation in conservation areas.

Masonry noun

Flemish Bond

/ ˈflɛmɪʃ bɒnd /

Also known as: Flemish brickwork, Dutch bond, header-stretcher bond

Definition

Flemish bond is a brickwork pattern in which each course alternates headers (bricks laid with their short end visible, 102.5mm face) and stretchers (bricks laid with their long face visible, 215mm face), with the headers centred over the stretchers in adjacent courses. This creates a distinctive square repeat pattern on the wall face. It is the dominant bond of Georgian, Regency, and Victorian brickwork in the UK and gives much traditional domestic architecture its characteristic appearance.

In practice

Laying Flemish bond requires careful setting out. On a 215mm solid wall, the headers tie across the full wall thickness - every other brick in each course is a header doing structural bonding work, alternating with a stretcher that lays along the wall face. The quoins (corners) require special closers (queen closers - bricks cut to 51mm wide) to maintain the bond around the corner without a straight joint appearing. Half-brick piers or short returns can be particularly challenging to bond correctly in Flemish.

In a modern cavity wall, genuine Flemish bond on the outer leaf is impossible (there is no wall thickness to tie across) without using snap headers - cut half-bricks laid header-style to simulate the appearance of Flemish bond without tying through the wall. Snap headers are standard practice and perfectly acceptable aesthetically. On extensions to Georgian or Victorian buildings in conservation areas, planners often require snap-header Flemish bond on the outer face to match the host building.

Building Regulations

Structural (Part A)Bond pattern affects wall strength - solid walls must be properly bonded

Conservation areasBond pattern may be specified by planning conditions to match existing

Masonry standardBS EN 1996-1-1 (Eurocode 6) - Design of masonry structures

Approved Document A requires masonry walls to be constructed with proper bonding to achieve their designed structural performance. In solid wall construction, the header bricks that cross the wall thickness are critical to structural integrity - an unbonded cavity without ties is significantly weaker than a well-bonded solid wall. In conservation areas, matching the bonding pattern of the existing building may be required by planning condition as a condition of granting consent for new extensions or alterations.

Full Building Regulations guidance

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Flemish Bond

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