Types of bonds

Masonry Construction, April, 2003 by Bill Kjorlien

Bonds serve a variety of purposes, depending on the type of brickwork that is designed and built. By definition, a bond is an arrangement of built-up brick or other units laid so that their overlapping thoroughly ties the units together, which enables the whole to act as a unit in resisting stresses.

Bonds were developed as aesthetically pleasing means of strengthening a multi-wythe wall. The majority of brickwork presently being built in the United States is veneer, so bonds are largely decorative. An understanding of the basic bond types enhances the ability of the designer and mason to build beautiful brickwork with authentic patterns.

Three types

Fundamentally, there are only three types of bond in good brickwork: running bond, English bond, and Flemish bond. The multitude of diagonal pattern bonds are simply variations of the latter two types. English bond consists of alternating courses of headers and stretchers. Flemish bond uses alternating headers and stretchers in each course.

English corners and Dutch corners (Fig. 1 and 2) distinguish the two distinct methods of starting corners in English and Flemish bonds. To correctly align the head joints in English brickwork, it is necessary to introduce a unit one half a header in width at the corner. When a brick is split along its length, it is a "closer." In veneer English bond, a 2-inch piece is laid against the header at the corner.

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In Dutch brickwork, the closer (2-inch piece) is eliminated and a three-quarter brick is laid against the header at the corner. If a closer is used, never place it at the corner. Start with a full header and follow with the closer.

Running bond, according to the definition above, is technically not a bond since it is composed entirely of stretchers. Common bond, also called American bond or running header bond, is typically five courses of running bond tied with a sixth course of headers.

Older bond

Common bond was the most economical and widely used type in the U.S. in the era of multi-wythe loadbearing brickwork (Fig. 3). Five courses of stretchers are tied with one course of headers. A bond that repeats its pattern every sixth course with modular brick is ideal for architectural design, since six courses of modular brick are 16-inches high. This bond is attractive and familiar to most Americans.

[FIGURE 3 OMITTED]

Common bond is seen in many early and mid-20th century buildings. The visible brickwork is neatly laid, and vertical alignment on the headers is maintained in the six-course repetition. The headers also fall on center of stretchers and head joints in adjacent courses. On many occasions, multi-wythe brick backup or fire walls have been exposed to reveal common bond.

The "loft look" brickwork that was not built to be exposed, but now is, has become a very popular architectural feature, probably to the chagrin of the meticulous mason who never meant for brickwork that rough to be seen.

Bond pattern units

Figures 4 and 5 represent various units upon which all diagonal pattern bonds are based. These patterns are constructed by varying the bond and shifting the relation of the headers and stretchers in various ways.

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Whether structural or veneer, bonds in brickwork add unlimited interest and unique architectural opportunity to brickwork.

This article was based on Chapter 5 of the book "Practical Bricklaying" by Howard Briggs, B.S., M.A. (McGraw-Hill Book Co., 1924).

Bill Kjorlien is executive director of the Southern Brick Institute (SBI), which represents brick manufacturers in seven southeastern states. He is a bricklayer by trade, and has been with SBI since 1990. Kjorlien is an active member of ASTM, serves on the board of directors of The National Brick Research Center and The Masonry Society, and chaired the Masonry Technical Committee for Skills USA/National VICA for 10 years.