Masonry Design: A subtle difference in brick sizes

It may come as no surprise that bricks are available in different shapes and sizes. But, in at least one situation, the difference in size may be too subtle to notice until you see an area of infill that does not match the rest in coursing or joint thickness.

"Hey! Look at that small area of bricks with the fat mortar joints. What happened?"

Many U.S. buildings that are decades old were constructed of "standard" brick, each unit with an actual length of 8 inches. Today's "standard modular" brick of similar height and depth typically has a nominal length of 8 inches including the mortar head joint and an actual length of 7.625 inches, allowing for a .375 inch mortar head joint. (An actual length of 7.5 inches may also be available to accommodate a .5 inch head joint.) If you are renovating or adding to an existing brick building, it's a good idea to measure the existing brick. And, if you can't get a matching size, you may want to consider that in designing areas of infill.

(Similar issues can apply to matching existing brick color and bond. It may take a close look to spot a Flemish bond, a possible indication of underlying construction that differs from today's typical cavity wall or brick veneer construction.)