Masonry Bonds
Masonry Bonds tests the arrangement of bricks or blocks so that load is spread and vertical joints do not align from course to course. Expect English bond, Flemish bond, stretcher bond, header bond, garden-wall bond and rat-trap bond, plus terms such as course, bed joint, perpend, lap, quoin, queen closer and bat.
Core rules
- English bond alternates a header course and a stretcher course; it is strong and suitable for thick load-bearing walls.
- Flemish bond alternates headers and stretchers in each course; it gives good appearance but needs more facing bricks.
- Stretcher bond is common in half-brick walls and cavity walls; it is not a strong bond for a one-brick load-bearing wall by itself.
- A lap of at least one-quarter brick is general; continuous vertical joints are a defect.
- Quoins at corners must be built true and toothed for later work.
Worked example
A 5 m long × 3 m high wall is 230 mm thick. Wall area = 15 m2; volume = 15 × 0.23 = 3.45 m3. Using the nominal modular rate of 500 bricks per m3, the wall needs 3.45 × 500 = 1,725 bricks. Add 5% for breakage and cutting: 1,725 × 1.05 = 1,811 bricks. The bond chosen affects appearance and cutting, not this nominal volume calculation.
Traps that cost marks
Counting a half-brick wall as 230 mm thick, forgetting the mortar module, or accepting a straight vertical joint through several courses are common errors. Do not use stretcher bond for a thick load-bearing pier without checking the design.
Key points
- English bond = alternating header and stretcher courses.
- Flemish bond = headers and stretchers alternate within each course.
- Continuous vertical joints are a structural and visual defect.
- Allow at least a quarter-brick lap unless the design states otherwise.
- Build quoins true and leave toothing for continuation.