Gauge is the vertical measure applied to the height of brickwork in terms of the combined thickness of bricks and the mortar bed joints between courses. Bricklayers will often check gauge by measuring with a tape, in multiples of the thickness of a course of bricks. For example, 65mm brick + 10mm bed joint = 75mm gauge. Typically, and for convenience, bricklayers will check that every fourth course measures 300mm. There are measuring tapes available that are specifically marketed at bricklayers, marked out for the purpose of gauging brickwork.
A more traditional alternative still favoured by many bricklayers, however, is a gauge lath that is marked with 75mm graduations, made from a length of timber 50mm x 20mm in section (or similar). This device makes gauging the height of every course a simple task. The marks on a gauge lath are made with permanent, shallow saw cuts rather than a pencil.
Fig. 68 Gauge lath.