Course gauge is the repeated vertical distance used to set out masonry. It determines the level of each horizontal joint. Both the brick height and the mortar joint contribute to this distance.
Add brick height and one bed joint
Take the actual height of your brick and add the chosen horizontal mortar joint, called the bed joint. A 50 mm brick with a 12 mm joint gives a 62 mm course gauge. Keep every dimension in the same unit while calculating.
Why five courses do not always mean five joints
Five repeated modules of 62 mm total 310 mm, including five joints. A separate stack of five bricks has only four internal joints: 5 × 50 + 4 × 12 = 298 mm. Add any joint below or above separately. Decide exactly where your measurement starts and ends.
5 × 50 + 4 × 12 = 298 mm
Fit whole courses into a height
Choose a whole number of courses and work backwards to the joint. For 620 mm containing ten repeated modules, the gauge is 620 ÷ 10 = 62 mm and the joint is 62 − 50 = 12 mm. If the resulting joint is unsuitable, reconsider the course count or overall dimension.
Course gauge in jack arches and gable weaving
A jack arch height can align with the courses alongside the opening. In gable weaving, vertical course gauge differs from the distance along a sloping line. Measure each in its specified direction; do not use the sloping distance as a vertical joint size. The chosen division can produce an actual gauge different from your preferred one.